Load control system having an energy savings mode

ABSTRACT

A load control system for a building having a heating and cooling system and a window located in a space of the building controls amount of daylight entering the window in order to attempt to reduce the power consumption of the heating and cooling system, and adjusts amount of daylight entering the window if the heating and cooling system is not saving energy. A motorized window treatment of the load control system is operable to move a fabric covering the window in a first direction, and a temperature control device is operable to subsequently determine if the heating and cooling system is consuming more energy than when the fabric was in the initial position. The motorized window treatment then moves the fabric in a second direction opposite the first direction if the heating and cooling system is consuming more energy than when the fabric was in the initial position.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a non-provisional application ofcommonly-assigned, U.S. Provisional Patent Application No. 61/230,001,filed Jul. 30, 2009, and U.S. Provisional Application No. 61/239,988,filed Sep. 4, 2009, both entitled LOAD CONTROL SYSTEM HAVING AN ENERGYSAVINGS MODE, the entire disclosures of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a load control system for a pluralityof electrical loads in a building, and more particularly, to a loadcontrol system for controlling the lighting intensities of lightingloads, the positions of motorized window treatments, and the temperatureof the building in order to reduce the total power consumption of theload control system.

2. Description of the Related Art

Reducing the total cost of electrical energy is an important goal formany electricity consumers. The customers of an electrical utilitycompany are typically charged for the total amount of energy consumedduring a billing period. However, since the electrical utility companymust spend money to ensure that its equipment (e.g., an electricalsubstation) is able to provide energy in all situations, including peakdemand periods, many electrical utility companies charge theirelectricity consumers at rates that are based on the peak powerconsumption during the billing period, rather than the average powerconsumption during the billing period. Thus, if an electricity consumerconsumes power at a very high rate for only a short period of time, theelectricity consumer will face a significant increase in its total powercosts.

Therefore, many electricity consumers use a “load shedding” technique toclosely monitor and adjust (i.e., reduce) the amount of power presentlybeing consumed by the electrical system. Additionally, the electricityconsumers “shed loads”, i.e., turn off some electrical loads, if thetotal power consumption nears a peak power billing threshold establishedby the electrical utility. Prior art electrical systems of electricityconsumers have included power meters that measure the instantaneoustotal power being consumed by the system. Accordingly, a buildingmanager of such an electrical system is able to visually monitor thetotal power being consumed. If the total power consumption nears abilling threshold, the building manager is able to turn off electricalloads to reduce the total power consumption of the electrical system.

Many electrical utility companies offer a “demand response” program tohelp reduce energy costs for their customers. With a demand responseprogram, the electricity consumers agree to shed loads during peakdemand periods in exchange for incentives, such as reduced billing ratesor other means of compensation. For example, the electricity utilitycompany may request that a participant in the demand response programshed loads during the afternoon hours of the summer months when demandfor power is great. Examples of lighting control systems that areresponsive to demand response commands are described in greater detailin commonly-assigned U.S. patent application Ser. No. 11/870,889, filedOct. 11, 2007, entitled METHOD OF LOAD SHEDDING TO REDUCE THE TOTALPOWER CONSUMPTION OF A LOAD CONTROL SYSTEM, and U.S. Pat. No. 7,747,357,issued Jun. 29, 2010, entitled METHOD OF COMMUNICATING A COMMAND FORLOAD SHEDDING OF A LOAD CONTROL SYSTEM, the entire disclosures of whichare hereby incorporated by reference.

Some prior art lighting control systems have offered a load sheddingcapability in which the intensities of all lighting loads are reduced bya fixed percentage, e.g., by 25%, in response to an input provided tothe system. The input may comprise an actuation of a button on a systemkeypad by a building manager. Such a lighting control system isdescribed in commonly-assigned U.S. Pat. No. 6,225,760, issued May 1,2001, entitled FLUORESCENT LAMP DIMMER SYSTEM, the entire disclosure ofwhich is hereby incorporated by reference.

Some prior art load control systems have provided for control of bothelectrical lighting loads (to control the amount of artificial light ina space) and motorized window treatments (to control the amount ofdaylight entering the space). Such load control systems have operated toachieve a desired lighting intensity on task surfaces in the space, tomaximize the contribution of the daylight provided to the total lightillumination in the space (i.e., to provide energy savings), and/or tominimize sun glare in the space. An example of a load control system forcontrol of both electrical lighting loads and motorized windowtreatments is described in greater detail in commonly-assigned U.S. Pat.No. 7,111,952, issued Sep. 26, 2006, entitled SYSTEM TO CONTROL DAYLIGHTAND ARTIFICIAL ILLUMINATION AND SUN GLARE IN A SPACE, the entiredisclosure of which is hereby incorporated by reference.

In addition, prior art heating, ventilation, and air-conditioning (HVAC)control systems for control of the temperature in a building and mayoperate to minimize energy consumption. However, there exists a need fora single load control system that controls the lighting intensities oflighting loads, the positions of motorized window treatments, and thetemperature of the building in order to reduce the total powerconsumption of the load control system.

SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a load controlsystem for a building having a heating and cooling system and a windowlocated in a space of the building controls amount of daylight enteringthe window in order to attempt to reduce the power consumption of theheating and cooling system, and adjusts amount of daylight entering thewindow if the heating and cooling system is not saving energy. The loadcontrol system comprises a motorized window treatment having a windowtreatment fabric for covering the window, and a temperature controldevice for controlling a setpoint temperature of the heating and coolingsystem to thus control a present temperature in the building. Themotorized window treatment moves the fabric to an initial positionbetween a fully-open position in which the window is not covered and afully-closed position in which the window is covered. The motorizedwindow treatment is operable to move the fabric in a first direction,and the temperature control device is operable to subsequently determineif the heating and cooling system is consuming more energy than when thefabric was in the initial position. The motorized window treatment isoperable to move the fabric in a second direction opposite the firstdirection if the heating and cooling system is consuming more energythan when the fabric was in the initial position.

In addition, a temperature control device for controlling a heating andcooling system of a building is also described herein. The building hasa window located in a space of the building, and a load control systemfor adjusting the amount of daylight entering the space through thewindow. The temperature control device comprises a first communicationcircuit adapted to be coupled to the heating and cooling system, asecond communication circuit adapted to be coupled to the load controldevice for adjusting the amount of daylight entering the space, and acontroller coupled to the first communication circuit for controlling asetpoint temperature of the heating and cooling system to thus control apresent temperature in the building, and coupled to the secondcommunication circuit for transmitting digital messages to the loadcontrol system. The controller monitors the heating and cooling systemfor a predetermined time period to determine if the heating and coolingsystem is consuming more energy at the end of the predetermined timeperiod than at the beginning of the predetermined time period. Thecontroller transmits a digital message to the load control system if theheating and cooling system is consuming more energy at the end of thepredetermined time period than at the beginning of the predeterminedtime period, such that the load control system decreases the amount ofthe daylight entering the space in response to the transmitted digitalmessage.

A method of controlling a motorized window treatment comprising a windowtreatment fabric for covering a window in a space of the buildingcomprises: (1) moving the fabric to an initial position between afully-open position in which the window is not covered and afully-closed position in which the window is covered; (2) subsequentlymoving the fabric in a first direction; (3) determining if a heating andcooling system of the building is consuming more energy than when thefabric was in the initial position; and (4) moving the fabric in asecond direction opposite the first direction if the heating and coolingsystem is consuming more energy than when the fabric was in the initialposition.

According to another embodiment of the present invention, a load controlsystem for a building having a heating and cooling system and a windowis operable to control a temperature control device and a motorizedwindow treatment in response to a demand response command. Thetemperature control device adjusts a setpoint temperature of the heatingand cooling system to thus control a present temperature in thebuilding, so as to decrease the power consumption of the heating andcooling system. The motorized window treatment comprising a windowtreatment fabric for covering the window, and moves the fabric between afully-open position in which the window is not covered and afully-closed position in which the window is covered. The motorizedwindow treatment moves the fabric to a position above the fully-closedposition in response to the demand response command. The temperaturecontrol device monitors the heating and cooling system after receivingthe demand response command, and the motorized window treatment movesthe fabric to the fully-closed position if the heating and coolingsystem is not consuming less energy after receiving the demand responsecommand.

Other features and advantages of the present invention will becomeapparent from the following description of the invention that refers tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of a centralized load controlsystem according to a first embodiment of the present invention;

FIG. 2 is a simplified side view of an example of a space of a buildinghaving a window covered by one of the motorized roller shades of theload control system of FIG. 1;

FIG. 3A is a side view of the window of FIG. 2 illustrating a sunlightpenetration depth;

FIG. 3B is a top view of the window of FIG. 2 when the sun is directlyincident upon the window;

FIG. 3C is a top view of the window of FIG. 2 when the sun is notdirectly incident upon the window;

FIG. 4 is a simplified flowchart of a timeclock configuration procedureexecuted periodically by a controller of the load control system of FIG.1 according to the first embodiment of the present invention;

FIG. 5 is a simplified flowchart of an optimal shade position procedureexecuted by the controller of the load control system of FIG. 1according to the first embodiment of the present invention;

FIGS. 6A-6C show example plots of optimal shade positions of themotorized roller shades of the load control system of FIG. 1 ondifferent facades of the building during different days of the yearaccording to the first embodiment of the present invention;

FIG. 7 is a simplified flowchart of a timeclock event creation procedureexecuted by the controller of the load control system of FIG. 1according to the first embodiment of the present invention;

FIGS. 8A-8C show example plots of controlled shade positions of themotorized roller shades of the load control system of FIG. 1 ondifferent facades of the building during different days of the yearaccording to the first embodiment of the present invention;

FIG. 9 is a simplified flowchart of a daylighting procedure executedperiodically by the controller of the load control system of FIG. 1 whendaylighting is enabled;

FIG. 10A is a simplified flowchart of a demand response messageprocedure executed by the controller of the load control system of FIG.1 according to the first embodiment of the present invention;

FIG. 10B is a simplified flowchart of a load control procedure executedperiodically by the controller of the load control system of FIG. 1according to the first embodiment of the present invention;

FIG. 11 is a simplified flowchart of a normal control procedure executedby the controller of the load control system of FIG. 1 according to thefirst embodiment of the present invention;

FIGS. 12A and 12B are simplified flowcharts of a demand response controlprocedure executed by the controller of the load control system of FIG.1 according to the first embodiment of the present invention;

FIG. 13 is a simplified flowchart of a timeclock execution procedureexecuted periodically by the controller of the load control system ofFIG. 1 according to the first embodiment of the present invention;

FIG. 14 is a simplified flowchart of a daylighting monitoring procedureexecuted by the controller of the load control system of FIG. 1according to the first embodiment of the present invention;

FIG. 15A is a simplified flowchart of a modified schedule procedureexecuted by the controller of the load control system of FIG. 1according to the first embodiment of the present invention;

FIG. 15B is a simplified flowchart of an HVAC monitoring procedureexecuted by the controller of the load control system of FIG. 1according to the first embodiment of the present invention;

FIG. 16 is a simplified flowchart of a planned demand response procedureexecuted by the controller of the load control system of FIG. 1according to a second embodiment of the present invention;

FIG. 17 is a simplified flowchart of the pre-condition timeclock eventprocedure executed by the controller of the load control system of FIG.1 according to the second embodiment of the present invention;

FIG. 18 is a simplified flowchart of the planned demand responsetimeclock event procedure executed by the controller of the load controlsystem of FIG. 1 according to the second embodiment of the presentinvention;

FIGS. 19A and 19B are simplified flowcharts of a demand response levelprocedure executed by the controller of the load control system of FIG.1 according to a third embodiment of the present invention;

FIG. 20 is a simplified block diagram of a distributed load controlsystem according to a fourth embodiment of the present invention;

FIG. 21A is a front view of a temperature control device of the loadcontrol system of FIG. 20 showing a cover plate open;

FIG. 21B is a front view of the temperature control device of FIG. 21Ashowing the cover plate open;

FIG. 22 is a perspective view of a wireless temperature sensor of theload control system of FIG. 20; and

FIG. 23 is a simplified block diagram of the temperature control deviceof FIG. 21A.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing summary, as well as the following detailed description ofthe preferred embodiments, is better understood when read in conjunctionwith the appended drawings. For the purposes of illustrating theinvention, there is shown in the drawings an embodiment that ispresently preferred, in which like numerals represent similar partsthroughout the several views of the drawings, it being understood,however, that the invention is not limited to the specific methods andinstrumentalities disclosed.

FIG. 1 is a simplified block diagram of a centralized load controlsystem 100 that may be installed in a building (such as a commercialbuilding) according to a first embodiment of the present invention. Theload control system 100 comprises a multi-zone lighting control device110 that is operable to control the amount of power delivered from analternating-current (AC) power source (not shown) to one or morelighting loads 112 for adjusting the intensities of the lighting loads.The lighting load 112 may be located in a space 160 (FIG. 2) of thebuilding to thus control the amount of electric light (i.e., artificiallight) in the space. The lighting loads 112 may comprise, for example,incandescent lamps, halogen lamps, gas discharge lamps, fluorescentlamps, compact fluorescent lamps, high-intensity discharge (HID) lamps,magnetic low-voltage (MLV) lighting loads, electronic low-voltage (ELV)lighting loads, light-emitting diode (LED) light sources, hybrid lightsources comprising two or more different types of lamps, and any otherelectrical light sources, or combination thereof, that provideillumination. In addition, the load control system 100 may compriseadditional multi-zone lighting control devices 110 as well assingle-zone lighting control devices, such as, electronic dimmingballasts, LED drivers, and dimmer switches.

The lighting control device 110 is operable to control a presentlighting intensity L_(PRES) of each of the lighting loads 112 from aminimum lighting intensity L_(MIN) to a maximum lighting intensityL_(MAX). The lighting control device 110 is operable to “fade” thepresent lighting intensity L_(PRES), i.e., control the present lightingintensity from a first lighting intensity to a second lighting intensityover a period of time. Fade rates of a lighting control device aredescribed in greater detail in commonly-assigned U.S. Pat. No.5,248,919, issued Sep. 29, 1993, entitled LIGHTING CONTROL DEVICE, theentire disclosure of which is hereby incorporated by reference.

The lighting control device 110 comprises a first set of buttons 114,which may be actuated by a user to allow for manual control of theintensities of the lighting loads 112, i.e., to allow an occupant tocontrol the intensities of the lighting load 112 to desired intensitylevels L_(DES). Actuations of the buttons 114 may cause the lightingcontrol device 110 to select one or more lighting presets (i.e.,“scenes”). The first set of buttons 114 may also comprise raise andlower buttons for respectively raising and lowering the intensities ofall (or a subset) of the lighting loads 112 in unison. The lightingcontrol device 110 is connected to a wired communication link 116 and isoperable to transmit and receive digital messages via the communicationlink. Alternatively, the communication link could comprise a wirelesscommunication link, such as, for example, a radio-frequency (RF)communication link or an infrared (IR) communication link.

The load control system 100 also comprises one or more daylight controldevices, for example, motorized window treatments, such as motorizedroller shades 120. The motorized roller shades 120 of the load controlsystem 100 may be positioned in front of one or more windows forcontrolling the amount of daylight (i.e., natural light) entering thebuilding. The motorized roller shades 120 each comprise a flexible shadefabric 122 rotatably supported by a roller tube 124. Each motorizedroller shade 120 is controlled by an electronic drive unit (EDU) 126,which may be located inside the roller tube 124. The electronic driveunit 126 may be powered directly from the AC power source or from anexternal direct-current (DC) power supply (not shown). The electronicdrive unit 126 is operable to rotate the respective roller tube 124 tomove the bottom edge of the shade fabric 122 to a fully-open positionand a fully-closed position, and to any position between the fully-openposition and the fully-closed position (e.g., a preset position).Specifically, the motorized roller shades 120 may be opened to allowmore daylight to enter the building and may be closed to allow lessdaylight to enter the building. In addition, the motorized roller shades120 may be controlled to provide additional insulation for the building,e.g., by moving to the fully-closed position to keep the building coolin the summer and warm in the winter. Examples of electronic drive unitsfor motorized roller shades are described in commonly-assigned U.S. Pat.No. 6,497,267, issued Dec. 24, 2002, entitled MOTORIZED WINDOW SHADEWITH ULTRAQUIET MOTOR DRIVE AND ESD PROTECTION, and U.S. Pat. No.6,983,783, issued Jan. 10, 2006, entitled MOTORIZED SHADE CONTROLSYSTEM, the entire disclosures of which are hereby incorporated byreference.

Alternatively, the motorized roller shades 120 could comprise tensionedroller shade systems, such that the motorized roller shades 120 may bemounted in a non-vertical manner, for example, horizontally in askylight. An example of a tensioned roller shade system that is able tobe mounted in a skylights is described in commonly-assigned U.S. patentapplication Ser. No. 12/061,802, filed Apr. 3, 2008, entitledSELF-CONTAINED TENSIONED ROLLER SHADE SYSTEM, the entire disclosure ofwhich in hereby incorporated by reference. In addition, the daylightcontrol devices of the load control system 100 could alternativelycomprise controllable window glazings (e.g., electrochromic windows),controllable exterior shades, controllable shutters or louvers, or othertypes of motorized window treatments, such as motorized draperies, romanshades, or blinds. An example of a motorized drapery system is describedin commonly-assigned U.S. Pat. No. 6,935,403, issued Aug. 30, 2005,entitled MOTORIZED DRAPERY PULL SYSTEM, the entire disclosure of whichin hereby incorporated by reference.

Each of the electronic drive units 126 is coupled to the communicationlink 116, such that the electronic drive unit may control the positionof the respective shade fabric 122 in response to digital messagesreceived via the communication link. The lighting control device 110 maycomprise a second set of buttons 118 that provides for control of themotorized roller shades 120. The lighting control device 110 is operableto transmit a digital message to the electronic drive units 126 inresponse to actuations of any of the second set of buttons 118. The useris able to use the second set of buttons 118 to open or close themotorized roller shades 120, adjust the position of the shade fabric 122of the roller shades, or set the roller shades to preset shade positionsbetween the fully open position and the fully closed position.

The load control system 100 comprise one or more temperature controldevices 130, which are also coupled to the communication link 116, andmay be powered, for example, from the AC power source, an external DCpower supply, or an internal battery. The temperature control devices130 are also coupled to a heating, ventilation, and air-conditioning(HVAC) control system 132 (i.e., a “heating and cooling” system) via anHVAC communication link 134, which may comprise, for example, a networkcommunication link such as an Ethernet link. Each temperature isoperable to control the HVAC system 132 to a cooling mode in which theHVAC system is cooling the building, and to a heating mode in which theHVAC system is heating the building. The temperature control devices 130each measure a present temperature T_(PRES) in the building and transmitappropriate digital messages to the HVAC system to thus control thepresent temperature in the building towards a setpoint temperatureT_(SET). Each temperature control device 130 may comprise a visualdisplay 135 for displaying the present temperature T_(PRES) in thebuilding or the setpoint temperature T_(SET). In addition, eachtemperature control device 130 may comprise raise and lower temperaturebuttons 136, 138 for respectively raising and lowering the setpointtemperature T_(SET) to a desired temperature T_(DES) as specified by theoccupant in the building. Each temperature control device 130 is alsooperable to adjust the setpoint temperature T_(SET) in response todigital messages received via the communication link 116.

The load control system 100 further comprises one or more controllableelectrical receptacles 140 for control of one or more plug-in electricalloads 142, such as, for example, table lamps, floor lamps, printers, faxmachines, display monitors, televisions, coffee makers, and watercoolers. Each controllable electrical receptacle 140 receives power fromthe AC power source and has an electrical output to which a plug of theplug-in electrical load 142 may be inserted for thus powering theplug-in load. Each controllable electrical receptacle 140 is operable toturn on and off the connected plug-in electrical load 142 in response todigital messages received via the communication link. In addition, thecontrollable electrical receptacles 140 may be able to control theamount of power delivered to the plug-in electrical load 142, e.g., todim a plug-in lighting load. Additionally, the load control system 100could comprise one or more controllable circuit breakers (not shown) forcontrol of electrical loads that are not plugged into electricalreceptacles, such as a water heater.

The load control system 100 may also comprise a controller 150, whichmay be coupled to the communication link 116 for facilitating control ofthe lighting control devices 110, the motorized roller shades 120, thetemperature control devices 130, and the controllable electricalreceptacles 140 of the load control system 100. The controller 150 isoperable to control the lighting control devices 110 and the motorizedroller shades 120 to control a total light level in the space 160 (i.e.,the sum of the artificial and natural light in the space). Thecontroller 150 is further operable to control the load control system100 to operate in an energy savings mode. Specifically, the controller150 is operable to transmit individual digital messages to each of thelighting control devices 110, the motorized roller shades 120, thetemperature control devices 130, and the controllable electricalreceptacles 140 to control the intensities of the lighting loads 112,the positions of the shade fabrics 122, the temperature of the building,and the state of the plug-in electrical loads 142, respectively, so asto reduce the total power consumption of the load control system 100 (aswill be described in greater detail below). The controller 150 may befurther operable to monitor the total power consumption of the loadcontrol system 100.

The load control system 100 may further comprise an occupancy sensor 152for detecting an occupancy condition or a vacancy condition in the spacein which the occupancy sensor in mounted, and a daylight sensor 154 formeasuring an ambient light intensity L_(AMB) in the space in which thedaylight sensor in mounted. The occupancy sensor 152 and the daylightsensor 154 may be coupled to the lighting control device 110 (as shownin FIG. 1). Alternatively, the occupancy sensor 152 and the daylightsensor 154 may be coupled to the communication link 116 or directly tothe controller 150.

The controller 150 is operable to control the lighting control device110, the motorized roller shades 120, the temperature control devices130, and the controllable electrical receptacles 140 in response to anoccupancy condition or a vacancy condition detected by the occupancysensor 152, and/or in response to the ambient light intensity L_(AMB)measured by the daylight sensor 154. For example, the controller 150 maybe operable to turn on the lighting loads 112 in response to detectingthe presence of an occupant in the vicinity of the occupancy sensor 152(i.e., an occupancy condition), and to turn off the lighting loads inresponse to detecting the absence of the occupant (i.e., a vacancycondition). In addition, the controller 150 may be operable to increasethe intensities of the lighting loads 112 if the ambient light intensityL_(AMB) detected by the daylight sensor 154 is less than a setpointlight intensity L_(SET), and to decrease the intensities of the lightingload if the ambient light intensity L_(AMB) is greater than the setpointlight intensity L_(SET).

Examples of occupancy sensors are described in greater detail inco-pending, commonly-assigned U.S. patent application Ser. No.12/203,500, filed Sep. 3, 2008, entitled BATTERY-POWERED OCCUPANCYSENSOR; and U.S. patent application Ser. No. 12/371,027, filed Feb. 13,2009, entitled METHOD AND APPARATUS FOR CONFIGURING A WIRELESS SENSOR,the entire disclosures of which are hereby incorporated by reference.Examples of daylight sensors are described in greater detail incommonly-assigned U.S. patent application Ser. No. 12/727,923, filedMar. 19, 2010, entitled METHOD OF CALIBRATING A DAYLIGHT SENSOR; andU.S. patent application Ser. No. 12/727,956, filed Mar. 19, 2010,entitled WIRELESS BATTERY-POWERED DAYLIGHT SENSOR, the entiredisclosures of which are hereby incorporated by reference.

The controller 150 may also be connected to a network communication link156, e.g., an Ethernet link, which may be coupled to a local areanetwork (LAN), such as an intranet, or a wide area network (WAN), suchas the Internet. The network communication link 156 may also comprise awireless communication link allowing for communication on a wirelessLAN. For example, the controller 150 may be operable to receive a demandresponse (DR) command (e.g., an “immediate” demand response command)from an electrical utility company as part of a demand response program.In response to receiving an immediate demand response command, thecontroller 150 will immediately control the load control system 100 toreduce the total power consumption of the load control system.

According to alternative embodiments of the present invention, thedemand response command may also comprise one of a plurality of demandresponse levels or a planned demand response command indicating anupcoming planned demand response event as will be describe in greaterdetail below. While the present invention is described with thecontroller 150 connected to the network communication link 156 forreceipt of the demand response commands, the one or more of the lightingcontrol devices 110 could alternatively be coupled to the networkcommunication link 156 for control of the lighting loads 112, themotorized roller shades 120, the temperature control devices 130, andthe controllable electrical receptacles 140 in response to the demandresponse commands.

The controller 150 may comprise an astronomical time clock fordetermining the present time of day and year. Alternatively, thecontroller 150 could retrieve the present time of the year or day fromthe Internet via the network communication link 156.

To maximize the reduction in the total power consumption of the loadcontrol system 100, the controller 150 is operable to control the loadcontrol system 100 differently depending upon whether the HVAC system132 is presently heating or cooling. For example, the controller 150 mayincrease the setpoint temperatures T_(SET) of each of the temperaturecontrol devices 130 when the HVAC system 132 is presently cooling andmay decrease the setpoint temperatures T_(SET) when the HVAC system ispresently heating in order to save energy. Alternatively, the controller150 could control the setpoint temperature T_(SET) of the temperaturecontrol device 130 differently depending on whether the present time ofthe year is during a first portion of the year, e.g., the “summer”(i.e., the warmer months of the year), or during a second portion of theyear, e.g., the “winter” (i.e., the colder months of the year). As usedherein, the “summer” refers to the warmer half of the year, for example,from approximately May 1 to approximately October 31, and the “winter”refers to the colder half of the year, for example, from approximatelyNovember 1 to approximately April 30. In addition, the controller 150could alternatively control the setpoint temperature T_(SET) of thetemperature control device 130 differently depending on the temperatureexternal to the building.

The controller 150 may be operable to operate in an “out-of-box” mode ofoperation immediately after being installed and powered for the firsttime. Specifically, the controller 150 may be operable to control thelighting control devices 110, the motorized roller shades 120, thetemperature control devices 130, and the controllable electricalreceptacles 140 according to pre-programmed out-of-box settings inresponse to receiving a demand response command via the networkcommunication link 156. For example, in response to receiving the demandresponse command when in the out-of-box mode, the controller 150 may dimthe lighting loads 112 by a predetermined percentage ΔL_(OOB), e.g., byapproximately 20% of the present lighting intensity L_(PRES) (such thatthe lighting loads 112 consume less power). In addition, the controller150 may close all of the motorized roller shades 120 to provideadditional insulation for the building (such that the HVAC system 132will consume less power) in response to receiving the demand responsecommand when in the out-of-box mode. Further, the controller 150 mayadjust the setpoint temperatures T_(SET) of the temperature controldevices 130 in response in response to receiving the demand responsecommand when in the out-of-box mode, for example, by increasing thesetpoint temperatures T_(SET) of each of the temperature control devicesby a predetermined increment ΔT_(OOB) (e.g., approximately 2° F.) whenthe HVAC system 132 is presently cooling the building, and decreasingthe setpoint temperatures T_(SET) of each of the temperature controldevices by the predetermined increment ΔT_(OOB) when the HVAC system ispresently heating the building, such that the HVAC system will consumeless power.

To maximize the reduction in the total power consumption of the loadcontrol system 100, the controller 150 may be configured using anadvanced programming procedure, such that the controller 150 operates ina programmed mode (rather than the out-of-box mode). For example, thecontroller 150 may be programmed to control the load control system 100differently depending upon whether one or more of the windows of thebuilding are receiving direct sunlight as will be described in greaterdetail below. The load control system 100 and the controller 150 may beprogrammed using, for example, a personal computer (PC) (not shown),having a graphical user interface (GUI) software. The programminginformation may be stored in a memory in the controller 150.

In addition, the controller 150 or one of the other control devices ofthe load control system 100 may be able to provide a visual indicationthat load control system is operating in the energy savings mode (i.e.,in response to a demand response command). For example, the lightingcontrol device 110 could comprise a visual indicator, such as alight-emitting diode (LED), which may be illuminated when the loadcontrol system 100 is operating in the energy savings mode. An exampleof a lighting control device for providing a visual indication of anenergy savings mode is described in greater detail in commonly-assignedU.S. patent application Ser. No. 12/474,950, filed May 29, 2009,entitled LOAD CONTROL DEVICE HAVING A VISUAL INDICATION OF AN ENERGYSAVINGS MODE, the entire disclosure of which is hereby incorporated byreference.

Alternatively, the load control system 100 could comprises a visualdisplay, such as an liquid-crystal display (LCD) screen, for providing avisual indication in the load control system 100 is operating in theenergy savings mode and for providing information regarding the totalpower consumption of the load control system and the amount of energysavings. An example of a visual display for providing energy savingsinformation is described in greater detail in commonly-assigned U.S.patent application Ser. No. 12/044,672, filed Mar. 7, 2008, SYSTEM ANDMETHOD FOR GRAPHICALLY DISPLAYING ENERGY CONSUMPTION AND SAVINGS, theentire disclosure of which is hereby incorporated by reference.

The controller 150 is operable to transmit digital messages to themotorized roller shades 120 to control the amount of sunlight enteringthe space 160 of the building to limit a sunlight penetration distanced_(PEN) in the space. The controller 150 comprises an astronomicaltimeclock and is able to determine a sunrise time t_(SUNRISE) and asunset time t_(SUNSET) for a specific day of the year. The controller150 transmits commands to the electronic drive units 126 toautomatically control the motorized roller shades 120 in response to ashade timeclock schedule as will be described in greater detail below.An example of a method of limiting the sunlight penetration distanced_(PEN) is a space is described in greater detail in commonly-assignedU.S. patent application Ser. No. 12/563,786, filed Sep. 21, 2009,entitled METHOD OF AUTOMATICALLY CONTROLLING A MOTORIZED WINDOWTREATMENT WHILE MINIMIZING OCCUPANT DISTRACTIONS, the entire disclosureof which is hereby incorporated by reference.

FIG. 2 is a simplified side view of an example of the space 160illustrating the sunlight penetration distance d_(PEN), which iscontrolled by one of the motorized roller shades 120. As shown in FIG.2, the building comprises a façade 164 (e.g., one side of a four-sidedrectangular building) having a window 166 for allowing sunlight to enterthe space. The space 160 also comprises a work surface, e.g., a table168, which has a height h_(WORK). The motorized roller shade 120 ismounted above the window 166, such that the shade fabric 122 hangs infront of the window, so as to control the amount of daylight (i.e.,natural light) that is admitted through the window. The electronic driveunit 126 rotates the roller tube 172 to move the shade fabric 170between a fully open position (in which the window 166 is not covered)and a fully closed position (in which the window 166 is fully covered).Further, the electronic drive unit 126 may control the position of theshade fabric 170 to one of a plurality of preset positions between thefully open position and the fully closed position.

The sunlight penetration distance d_(PEN) is the distance from thewindow 166 and the façade 164 at which direct sunlight shines into theroom. The sunlight penetration distance d_(PEN) is a function of aheight h_(WIN) of the window 166 and an angle φ_(F) of the façade 164with respect to true north, as well as a solar elevation angle θ_(S) anda solar azimuth angle φ_(S), which define the position of the sun in thesky. The solar elevation angle θ_(S) and the solar azimuth angle φ_(S)are functions of the present date and time, as well as the position(i.e., the longitude and latitude) of the building in which the space160 is located. The solar elevation angle θ_(S) is essentially the anglebetween a line directed towards the sun and a line directed towards thehorizon at the position of the building. The solar elevation angle θ_(S)can also be thought of as the angle of incidence of the sun's rays on ahorizontal surface. The solar azimuth angle φ_(S) is the angle formed bythe line from the observer to true north and the line from the observerto the sun projected on the ground.

The sunlight penetration distance d_(PEN) of direct sunlight onto thetable 168 of the space 160 (which is measured normal to the surface ofthe window 166) can be determined by considering a triangle formed bythe length l of the deepest penetrating ray of light (which is parallelto the path of the ray), the difference between the height h_(WIN) ofthe window 166 and the height h_(WORK) of the table 168, and distancebetween the table and the wall of the façade 164 (i.e., the sunlightpenetration distance d_(PEN)) as shown in the side view of the window166 in FIG. 3A, i.e.,tan(θ_(S))=(h _(WIN) −h _(WORK))/l,  (Equation 1)where θ_(S) is the solar elevation angle of the sun at a given date andtime for a given location (i.e., longitude and latitude) of thebuilding.

If the sun is directly incident upon the window 166, a solar azimuthangle φ_(S) and the façade angle φ_(F) (i.e., with respect to truenorth) are equal as shown by the top view of the window 166 in FIG. 3B.Accordingly, the sunlight penetration distance d_(PEN) equals the lengthl of the deepest penetrating ray of light. However, if the façade angleφ_(F) is not equal to the solar azimuth angle φ_(S), the sunlightpenetration distance d_(PEN) is a function of the cosine of thedifference between the façade angle φ_(F) and the solar azimuth angleφ_(S), i.e.,d _(PEN) =l·cos(|φ_(F)−φ_(S)|),  (Equation 2)as shown by the top view of the window 166 in FIG. 3C.

As previously mentioned, the solar elevation angle θ_(S) and the solarazimuth angle φ_(S) define the position of the sun in the sky and arefunctions of the position (i.e., the longitude and latitude) of thebuilding in which the space 160 is located and the present date andtime. The following equations are necessary to approximate the solarelevation angle θ_(S) and the solar azimuth angle φ_(S). The equation oftime defines essentially the difference in a time as given by a sundialand a time as given by a clock. This difference is due to the obliquityof the Earth's axis of rotation. The equation of time can beapproximated byE=9.87·sin(2B)−7.53·cos(B)−1.5·sin(B),  (Equation 3)where B=[360°·(N_(DAY)−81)]/364, and N_(DAY) is the present day-numberfor the year (e.g., N_(DAY) equals one for January 1, N_(DAY) equals twofor January 2, and so on).

The solar declination δ is the angle of incidence of the rays of the sunon the equatorial plane of the Earth. If the eccentricity of Earth'sorbit around the sun is ignored and the orbit is assumed to be circular,the solar declination is given by:δ=23.45°·sin [360°/365·(N _(DAY)+284)].  (Equation 4)The solar hour angle H is the angle between the meridian plane and theplane formed by the Earth's axis and current location of the sun, i.e.,H(t)={½·[t+E−(4·λ)+(60·t _(TZ))]}−180°,  (Equation 5)where t is the present local time of the day, λ is the local longitude,and t_(TZ) is the time zone difference (in unit of hours) between thelocal time t and Greenwich Mean Time (GMT). For example, the time zonedifference t_(TZ) for the Eastern Standard Time (EST) zone is −5. Thetime zone difference t_(TZ) can be determined from the local longitude λand latitude Φ of the building. For a given solar hour angle H, thelocal time can be determined by solving Equation 5 for the time t, i.e.,t=720+4·(H+λ)−(60·t _(TZ))−E.  (Equation 6)When the solar hour angle H equals zero, the sun is at the highest pointin the sky, which is referred to as “solar noon” time t_(SN), i.e.,t _(SN)=720+(4·λ)−(60·t _(TZ))−E.  (Equation 7)A negative solar hour angle H indicates that the sun is east of themeridian plane (i.e., morning), while a positive solar hour angle Hindicates that the sun is west of the meridian plane (i.e., afternoon orevening).

The solar elevation angle θ_(S) as a function of the present local timet can be calculated using the equation:θ_(S)(t)=sin⁻¹[cos(H(t))·cos(δ)·cos(Φ)+sin(δ)·sin(Φ)],  (Equation 8)wherein Φ is the local latitude. The solar azimuth angle φ_(S) as afunction of the present local time t can be calculated using theequation:φ_(S)(t)=180°·C(t)·cos⁻¹ [X(t)/cos(θ_(S)(t))],  (Equation 9)whereX(t)=[cos(H(t))·cos(δ)·sin(Φ)−sin(δ)·cos(Φ)],  (Equation 10)and C(t) equals negative one if the present local time t is less than orequal to the solar noon time t_(SN) or one if the present local time tis greater than the solar noon time t_(SN). The solar azimuth angleφ_(S) can also be expressed in terms independent of the solar elevationangle θ_(S), i.e.,φ_(S)(t)=tan⁻¹[sin(H(t))·cos(δ)/Y(t)],  (Equation 11)whereY(t)=[sin(δ)·cos(Φ)−cos(δ)·sin(Φ)·cos(H(t))].  (Equation 12)Thus, the solar elevation angle θ_(S) and the solar azimuth angle φ_(S)are functions of the local longitude λ and latitude Φ and the presentlocal time t and date (i.e., the present day-number N_(DAY)). UsingEquations 1 and 2, the sunlight penetration distance can be expressed interms of the height h_(WIN) of the window 166, the height h_(WORK) ofthe table 168, the solar elevation angle θ_(S), and the solar azimuthangle φ_(S).

According to the first embodiment of the present invention, themotorized roller shades 120 are controlled such that the sunlightpenetration distance d_(PEN) is limited to less than a desired maximumsunlight penetration distance d_(MAX) during all times of the day. Forexample, the sunlight penetration distance d_(PEN) may be limited suchthat the sunlight does not shine directly on the table 168 to preventsun glare on the table. The desired maximum sunlight penetrationdistance d_(MAX) may be entered, for example, using the GUI software ofthe PC, and may be stored in the memory in the controller 150. Inaddition, the user may also use the GUI software of the computer toenter the local longitude λ and latitude Φ of the building, the façadeangle φ_(F) for each façade 164 of the building, and other relatedprogramming information, which may also be stored in the memory of eachcontroller 150.

In order to minimize distractions to an occupant of the space 160 (i.e.,due to movements of the motorized roller shades), the controller 150controls the motorized roller shades 120 to ensure that at least aminimum time period T_(MIN) exists between any two consecutive movementsof the motorized roller shades. The minimum time period T_(MIN) that mayexist between any two consecutive movements of the motorized rollershades may be entered using the GUI software of the computer and may bealso stored in the memory in the controller 150. The user may selectdifferent values for the desired maximum sunlight penetration distanced_(MAX) and the minimum time period T_(MIN) between shade movements fordifferent areas and different groups of motorized roller shades 120 inthe building.

FIG. 4 is a simplified flowchart of a timeclock configuration procedure200 executed periodically by the controller 150 of the load controlsystem 100 to generate a shade timeclock schedule defining the desiredoperation of the motorized roller shades 120 of each of the façades 164of the building according to the first embodiment of the presentinvention. For example, the timeclock configuration procedure 200 may beexecuted once each day at midnight to generate a new shade timeclockschedule for one or more areas in the building. The shade timeclockschedule is executed between a start time t_(START) and an end timet_(END) of the present day. During the timeclock configuration procedure200, the controller 150 first performs an optimal shade positionprocedure 300 for determining optimal shade positions P_(OPT)(t) of themotorized roller shades 120 in response to the desired maximum sunlightpenetration distance d_(MAX) for each minute between the start timet_(START) and the end time t_(END) of the present day. The controller150 then executes a timeclock event creation procedure 400 to generatethe events of the shade timeclock schedule in response to the optimalshade positions P_(OPT)(t) and the user-selected minimum time periodT_(MIN) between shade movements. The events times of the shade timeclockschedule are spaced apart by multiples of the user-specified minimumtime period T_(MIN) between shade movements. Since the user may selectdifferent values for the desired maximum sunlight penetration distanced_(MAX) and the minimum time period T_(MIN) between shade movements fordifferent areas and different groups of motorized roller shades 120 inthe building, a different shade timeclock schedule may be created andexecuted for the different areas and different groups of motorizedroller shades in the building (i.e., the different façades 164 of thebuilding).

The shade timeclock schedule is split up into a number of consecutivetime intervals, each having a length equal to the minimum time periodT_(MIN) between shade movements. The controller 150 considers each timeinterval and determines a position to which the motorized roller shades120 should be controlled in order to prevent the sunlight penetrationdistance d_(PEN) from exceeding the desired maximum sunlight penetrationdistance d_(MAX) during the respective time interval. The controller 150creates events in the shade timeclock schedule, each having an eventtime equal to beginning of respective time interval and a correspondingposition equal to the position to which the motorized roller shades 104should be controlled in order to prevent the sunlight penetrationdistance d_(PEN) from exceeding the desired maximum sunlight penetrationdistance d_(MAX). However, the controller 150 will not create atimeclock event when the determined position of a specific time intervalis equal to the determined position of a preceding time interval (aswill be described in greater detail below). Therefore, the event timesof the shade timeclock schedule are spaced apart by multiples of theuser-specified minimum time period T_(MIN) between shade movements.

FIG. 5 is a simplified flowchart of the optimal shade position procedure300, which is executed by the controller 150 to generate the optimalshade positions P_(OPT)(t) for each minute between the start timet_(START) and the end time t_(END) of the shade timeclock schedule suchthat the sunlight penetration distance d_(PEN) will not exceed thedesired maximum sunlight penetration distance d_(MAX). The controller150 first retrieves the start time t_(START) and the end time t_(END) ofthe shade timeclock schedule for the present day at step 310. Forexample, the controller 150 could use the astronomical timeclock to setthe start time t_(START) equal to the sunrise time t_(SUNRISE) for thepresent day, and the end time t_(END) equal to the sunset timet_(SUNSET) for the present day. Alternatively, the start and end timest_(START), t_(END) could be set to arbitrary times, e.g., 6 A.M. and 6P.M, respectively.

Next, the controller 150 sets a variable time t_(VAR) equal to the starttime t_(START) at step 312 and determines a worst case façade angleφ_(F-WC) at the variable time t_(VAR) to use when calculating theoptimal shade position P_(OPT)(t) at the variable time t_(VAR).Specifically, if the solar azimuth angle φ_(S) is within a façade angletolerance φ_(TOL) (e.g., approximately 3°) of the fixed façade angleφ_(F) at step 314 (i.e., if φ_(F)−φ_(TOL)≦φ_(S)≦φ_(F)+φ_(TOL)), thecontroller 150 sets the worst case façade angle φ_(F-WC) equal to thesolar azimuth angle φ_(S) of the façade 164 at step 315. If the solarazimuth angle φ_(S) is not within the façade angle tolerance φ_(TOL) ofthe façade angle φ_(F) at step 314, the controller 150 then determinesif the façade angle φ_(F) plus the façade angle tolerance φ_(TOL) iscloser to the solar azimuth angle φ_(S) than the façade angle φ_(F)minus the façade angle tolerance φ_(TOL) at step 318. If so, thecontroller 150 sets the worst case façade angle φ_(F-WC) equal to thefaçade angle φ_(F) plus the façade angle tolerance φ_(TOL) at step 320.If the façade angle φ_(F) plus the façade angle tolerance φ_(TOL) is notcloser to the solar azimuth angle φ_(S) than the façade angle φ_(F)minus the façade angle tolerance φ_(TOL) at step 318, the controller 150sets the worst case façade angle φ_(F-WC) equal to the façade angleφ_(F) minus the façade angle tolerance φ_(TOL) at step 322.

At step 324, the controller 150 uses Equations 1-12 shown above and theworst case façade angle φ_(F-WC) to calculate the optimal shade positionP_(OPT)(t_(VAR)) that is required in order to limit the sunlightpenetration distance d_(PEN) to the desired maximum sunlight penetrationdistance d_(MAX) at the variable time t_(VAR). At step 326, thecontroller 150 stores in the memory the optimal shade positionP_(OPT)(t_(VAR)) determined in step 324. If the variable time t_(VAR) isnot equal to the end time t_(END) at step 328, the controller 150increments the variable time t_(VAR) by one minute at step 330 anddetermines the worst case façade angle φ_(F-WC) and the optimal shadeposition P_(OPT)(t_(VAR)) for the new variable time t_(VAR) at step 324.When the variable time t_(VAR) is equal to the end time t_(END) at step328, the optimal shade position procedure 300 exits.

Thus, the controller 150 generates the optimal shade positionsP_(OPT)(t) between the start time t_(START) and the end time t_(END) ofthe shade timeclock schedule using the optimal shade position procedure300. FIG. 6A shows an example plot of optimal shade positionsP_(OPT1)(t) of the motorized roller shades 120 on the west façade of thebuilding on January 1, where the building is located at a longitude λ ofapproximately 75° W and a latitude Φ of approximately 40° N. FIG. 6Bshows an example plot of optimal shade positions P_(OPT2)(t) of themotorized roller shades 120 on the north façade of the building onJune 1. FIG. 6C shows an example plot of optimal shade positionsP_(OPT3)(t) of the motorized roller shades 120 on the south façade ofthe building on April 1.

FIG. 7 is a simplified flowchart of the timeclock event creationprocedure 400, which is executed by the controller 150 in order togenerate the events of the shade timeclock schedule according to thefirst embodiment of the present invention. Since the shade timeclockschedule is split up into a number of consecutive time intervals, thetimeclock events of the timeclock schedule are spaced between the starttime t_(START) and the end time t_(END) by multiples of the minimum timeperiod T_(MIN) between shade movements, which is selected by the user.During the timeclock event creation procedure 400, the controller 150generates controlled shade positions P_(CNTL)(t), which comprise anumber of discrete events, i.e., step changes in the position of themotorized roller shades at the specific event times. The controller 150uses the controlled shade positions P_(CNTL)(t) to adjust the positionof the motorized roller shades during execution of the shade timeclockschedule. The resulting timeclock schedule includes a number of events,which are each characterized by an event time and a corresponding presetshade position.

The controller 150 uses the controlled shade positions P_(CNTL)(t) toadjust the position of the motorized roller shades 120 during executionof a timeclock execution procedure 900, which will be described ingreater detail below with reference to FIG. 13. The timeclock executionprocedure 900 is executed by the controller 150 periodically (e.g., onceevery minute) between the start time t_(START) and the end time t_(END)when the shade timeclock schedule is enabled. The shade timeclockschedule may be disabled, such that the timeclock execution procedure900 is not executed periodically, when the space 160 is unoccupied orwhen the controller 150 receives an immediate demand command via thenetwork communication link 156. At the end of the shade timeclockschedule (i.e., at the end time t_(END)), the controller 150 controlsthe position of the motorized roller shades 120 to a nighttime positionP_(NIGHT) (e.g., the fully-closed position P_(FC)) as will be describedin greater detail below with reference to FIG. 13.

FIG. 8A shows an example plot of controlled shade positions P_(CNTL1)(t)of the motorized roller shades 120 on the west façade of the building onJanuary 1 according to the first embodiment of the present invention.FIG. 8B shows an example plot of controlled shade positions P_(CNTL2)(t)of the motorized roller shades 120 on the north façade of the buildingon June 1 according to the first embodiment of the present invention.FIG. 8C shows an example plot of controlled shade positions P_(CNTL3)(t)of the motorized roller shades 120 on the south façade of the buildingon April 1 according to the first embodiment of the present invention.

The controller 150 examines the values of the optimal shade positionsP_(OPT)(t) during each of the time intervals of the shade timeclockschedule (i.e., the time periods between two consecutive timeclockevents) to determine a lowest shade position P_(LOW) during each of thetime intervals. During the timeclock event creation procedure 400, thecontroller 150 uses two variable times t_(V1), t_(V2) to define theendpoints of the time interval that the controller is presentlyexamining The controller 150 uses the variable times t_(V1), t_(V2) tosequentially step through the events of the shade timeclock schedule,which are spaced apart by the minimum time period T_(MIN) according tothe first embodiment of the present invention. The lowest shadepositions P_(LOW) during the respective time intervals becomes thecontrolled shade positions P_(CNTL)(t) of the timeclock events, whichhave event times equal to the beginning of the respective time interval(i.e., the first variable time t_(V1)).

Referring to FIG. 7, the controller 150 sets the first variable timet_(V1) equal to the start time t_(START) of the shade timeclock scheduleat step 410. The controller 150 also initializes a previous shadeposition P_(PREV) to the nighttime position P_(NIGHT) at step 610. Ifthere is enough time left before the end time t_(END) for the presenttimeclock event (i.e., if the first variable time t_(V1) plus theminimum time period T_(MIN) is not greater than the end time t_(END)) atstep 412, the controller 150 determines at step 414 if there is enoughtime for another timeclock event in the shade timeclock schedule afterthe present timeclock event. If the first variable time t_(V1) plus twotimes the minimum time period T_(MIN) is not greater than the end timet_(END) at step 414, the controller 150 sets the second variable timet_(V2) equal to the first variable time t_(V1) plus the minimum timeperiod T_(MIN) at step 416, such that the controller 150 will thenexamine the time interval between the first and second variable timest_(V1), t_(V2). If the first variable time t_(V1) plus two times theminimum time period T_(MIN) is greater than the end time t_(END) at step414, the controller 150 sets the second variable time t_(V2) equal tothe end time t_(END) at step 418, such that the controller 150 will thenexamine the time interval between the first variable time t_(V1) and theend time t_(END).

At step 420, the controller 150 determines the lowest shade positionP_(LOW) of the optimal shade positions P_(OPT)(t) during the presenttime interval (i.e., between the first variable time t_(V1) and thesecond variable time t_(V2) determined at steps 416 and 418). If, atstep 422, the previous shade position P_(PREV) is not equal to thelowest shade position P_(LOW) during the present time interval (asdetermined at step 420), the controller 150 sets the controlled shadeposition P_(CNTL)(t_(V1)) at the first variable time t_(V1) to be equalto the lowest shade position P_(LOW) of the optimal shade positionsP_(OPT)(t) during the present time interval at step 424. The controller150 then stores in memory a timeclock event having the event time t_(V1)and the corresponding controlled position P_(CNTL)(t_(V1)) at step 426and sets the previous shade position P_(PREV) equal to the newcontrolled position P_(CNTL)(t_(V1)) at step 428. If, at step 422, theprevious shade position P_(PREV) is equal to the lowest shade positionP_(LOW) during the present time interval, the controller 150 does notcreate a timeclock event at the first variable time t_(V1). Thecontroller 150 then begins to examine the next time interval by settingthe first variable time t_(V1) equal to the second variable time t_(V2)at step 430. The timeclock event creation procedure 400 loops aroundsuch that the controller 150 determines if there is enough time leftbefore the end time t_(END) for the present timeclock event at step 412.If the first variable time t_(V1) plus the minimum time period T_(MIN)is greater than the end time t_(END) at step 412, the controller enablesthe shade timeclock schedule at step 432 and the timeclock eventcreation procedure 400 exits.

FIG. 9 is a simplified flowchart of a daylighting procedure 500, whichis executed periodically by the controller 150 (e.g., once every second)when daylighting (i.e., control of the lighting loads 112 in response tothe ambient light intensity L_(AMB) measured by the daylight sensor 154)is enabled at step 510. When daylighting is not enabled at step 510, thedaylighting procedure 500 simply exits. When daylighting is enabled atstep 510, the controller 150 causes the daylight sensor 154 to measurethe ambient light intensity L_(AMB) at step 512. If the measured ambientlight intensity L_(AMB) is less than a setpoint (i.e., target) intensityL_(SET) at step 514, the controller 150 controls the lighting controldevice 110 to increase the present lighting intensity L_(PRES) of eachof the lighting loads 112 by a predetermined value ΔL_(SET) (e.g.,approximately 1%) at step 516 and the daylighting procedure 500 exits.If the measured ambient light intensity L_(AMB) is greater than thesetpoint intensity L_(SET) at step 518, the controller 150 decreases thepresent lighting intensity L_(PRES) of each of the lighting loads 112 bythe predetermined value ΔL_(SET) at step 520 and the daylightingprocedure 500 exits. If the measured ambient light intensity L_(AMB) isnot less than the setpoint intensity L_(SET) at step 514 and is notgreater than the setpoint intensity L_(SET) at step 518 (i.e., theambient light intensity L_(AMB) is equal to the setpoint intensityL_(SET)), the daylighting procedure 500 simply exits without adjustingthe present lighting intensity L_(PRES) of each of the lighting loads112.

FIG. 10A is a simplified flowchart of a demand response messageprocedure 600, which is executed by the controller 150 in response toreceiving an immediate demand response command via the networkcommunication link 156 at step 610. Whenever an immediate demandresponse command is received at step 610, the controller 150 simplyenables a demand response (DR) mode at step 612, before the demandresponse message procedure 600 exits.

FIG. 10B is a simplified flowchart of a load control procedure 650,which is executed by the controller 150 periodically, e.g., everyminute. If the demand response mode is not enabled at step 652, thecontroller 150 executes a normal control procedure 700 for controllingthe lighting control devices 110, the motorized roller shades 120, thetemperature control devices 130, and the controllable electricalreceptacles 140 during a normal mode of operation, e.g., to maximize thecomfort of the occupants of the spaces 160 of the building. On the otherhand, if the demand response mode is enabled at step 652 (i.e., inresponse to receiving an immediate demand response command during thedemand response message procedure 600), the controller 150 executes ademand response control procedure 800 for controlling the lightingcontrol devices 110, the motorized roller shades 120, the temperaturecontrol devices 130, and the controllable electrical receptacles 140 todecrease the energy consumption of the load control system 100, whilemaintaining the comfort of the occupants of the spaces 160 of thebuilding at acceptable levels. During the normal control procedure 700and the demand response command procedure 800, the controller 150controls the lighting control devices 110, the motorized roller shades120, the temperature control devices 130, and the controllableelectrical receptacles 140 in the different spaces 160 (or areas) of thebuilding on an area-by-area basis. For example, the controller 150 maycontrol the lighting control devices 110, the motorized roller shades120, the temperature control device 130, and the controllable electricalreceptacles 140 in a specific area differently depending upon whetherthe area is occupied or not.

FIG. 11 is a simplified flowchart of the normal control procedure 700executed periodically by the controller 150 when the controller isoperating in the normal mode of operation (i.e., every minute). If thearea is occupied at step 710, the controller 150 transmits at step 712one or more digital messages to the lighting control devices 110 so asto adjust the intensities of the lighting loads 112 to theuser-specified desired lighting intensity levels L_(DES) (e.g., asdetermined in response to actuations of the first set of buttons 114 ofthe lighting control devices 110). At step 714, the controller 150transmits digital messages to the controllable electrical receptacles140 to supply power to all of the plug-in electrical loads 142 in thearea. Next, the controller 150 transmits a digital message to thetemperature control device 130 at step 715 to control the setpointtemperature T_(SET) to the user-specified desired temperature T_(DES)(e.g., as determined in response to actuations of the raise and lowertemperature buttons 136, 138 of the temperature control device 130).Finally, the controller 150 enables the shade timeclock schedule (ascreated during the timeclock event creation procedure 400) at step 716,and the normal control procedure 700 exits. Accordingly, shortly afterthe normal control procedure 700 exits, the timeclock executionprocedure 900 will be executed in order to adjust the positions of themotorized roller shades 120 to the controlled positions P_(CNTL)(t)determined in the timeclock event creation procedure 400. In addition,the timeclock execution procedure 900 will be executed periodicallyuntil the shade timeclock schedule is disabled.

If the area is unoccupied at step 710, the controller 150 turns off thelighting load 112 in the area at step 718 and turns off designated(i.e., some) plug-in electrical loads 142 at step 720. For example, thedesignated plug-in electrical loads 142 that are turned off in step 720may comprise table lamps, floor lamps, printers, fax machines, waterheaters, water coolers, and coffee makers. However, other non-designatedplug-in electrical loads 142 are not turned off in step 720, such as,personal computers, which remain powered even when the area isunoccupied. If the HVAC system 132 is presently cooling the building atstep 722, the controller 150 increases the setpoint temperature T_(SET)of the temperature control device 130 by a predetermined incrementΔT_(NRM) _(—) _(COOL) (e.g., approximately 2° F.) at step 724, such thatthe setpoint temperature T_(SET) is controlled to a new setpointtemperature T_(NEW), i.e.,T _(NEW) =T _(SET) +ΔT _(NRM) _(—) _(COOL).  (Equation 13)The HVAC system 132 thus consumes less power when the area is unoccupiedand the setpoint temperature T_(SET) is increased to the new setpointtemperature T_(NEW).

The controller 150 then transmits digital messages to the electronicdrive units 126 of the motorized roller shades 120 to move all of theshade fabrics 122 to the fully-closed positions at step 726. Thecontroller 150 also disables the shade timeclock schedule at step 726,before the normal control procedure 700 exits. Since the shade fabrics122 will be completely covering the windows, the shade fabrics willblock daylight from entering the building and thus the shade fabricsprevent daylight from heating the building. Accordingly, the HVAC system132 will consume less power when the motorized roller shades 120 areclosed.

If the HVAC system 132 is presently heating the building at step 722,the controller 150 decreases the setpoint temperature T_(SET) of thetemperature control device 130 by a predetermined increment ΔT_(NRM)_(—) _(HEAT) (e.g., approximately 2° F.) at step 728, such that thesetpoint temperature T_(SET) is controlled to the new setpointtemperature T_(NEW), i.e.,T _(NEW) =T _(SET) −ΔT _(NRM) _(—) _(HEAT).  (Equation 14)Thus, the HVAC system 132 consumes less power when the area isunoccupied and the setpoint temperature T_(SET) is decreased to the newsetpoint temperature T_(NEW) during the winter months.

Before adjusting the positions of the motorized roller shades 120, thecontroller 150 first determines at step 730 if the façade 164 of thewindows in the area may be receiving direct sunlight, e.g., using theEquations 1-12 shown above. If the façade 164 of the area is notreceiving direct sunlight at step 730, the controller 150 causes theelectronic drive units 126 of the motorized roller shades 120 to moveall of the shade fabrics 122 to the fully-closed positions and disablesthe shade timeclock schedule at step 732, such that the shade fabricsprovide additional insulation for the building. Accordingly, the shadefabrics 122 will prevent some heat loss leaving the building and theHVAC system 132 may consume less power. However, if the façade 164 ofthe area may be receiving direct sunlight at step 730, the controller150 controls the motorized roller shade 120 to the fully-open positionsdisables the shade timeclock schedule at step 734 in order to takeadvantage of the potential heat gain through the windows due to thedirect sunlight. Rather than using the Equations 1-12 shown above tocalculate whether the window may or may not be receiving directsunlight, the load control system 100 may alternatively comprise one ormore photosensors mounted adjacent the windows in the space to determineif the window is receiving direct sunlight.

FIGS. 12A and 12B are simplified flowcharts of the demand responsecontrol procedure 800 executed periodically by the controller 150 whenthe controller is operating in the demand response mode of operation(i.e., once every minute after a demand response command is received).If the area is not occupied at step 810, the controller 150 turns offthe lighting loads 112 in the area at step 812 and turns off thedesignated plug-in electrical loads 142 at step 814. If the HVAC system132 is presently cooling the building at step 816, the controller 150increases the setpoint temperature T_(SET) of each of the temperaturecontrol devices 130 by a predetermined increment ΔT_(DR) _(—) _(COOL1)(e.g., approximately 3° F.) at step 818. The controller 150 thencontrols the motorized roller shades 120 to the fully-closed positionsand disables the shade timeclock schedule at step 820, such that theHVAC system 132 will consume less power.

If the HVAC system 132 is presently heating the building at step 816,the controller 150 decreases the setpoint temperatures T_(SET) of eachof the temperature control devices 130 by a predetermined incrementΔT_(DR) _(—) _(HEAT1) (e.g., approximately 3° F.) at step 822. If thefaçade 164 of the area is not receiving direct sunlight at step 824, thecontroller 150 moves all of the motorized roller shades 120 to thefully-closed positions to provide additional insulation for the buildingand disables the shade timeclock schedule at step 826, such that theHVAC system 132 will consume less power. If the façade 164 of the areamay be receiving direct sunlight at step 824, the controller 150controls the motorized roller shade 120 to the fully-open positions atstep 828 in order to take advantage of the potential heat gain throughthe windows due to the direct sunlight. The controller 150 also disablesthe shade timeclock schedule at step 828, before the demand responsecontrol procedure 800 exits.

Referring to FIG. 12B, if the area is occupied at step 810, thecontroller 150 transmits at step 830 one or more digital messages to thelighting control devices 110 to lower the present lighting intensitiesL_(PRES) of each of the lighting loads 112 by a predetermined percentageΔL_(DR) (e.g., by approximately 20% of the present lighting intensityL_(PRES)). The lighting control device 110 fades the present lightingintensity L_(PRES) of each of the lighting loads 112 over a first fadetime period (e.g., approximately thirty seconds) to a new lightingintensity L_(NEW), i.e.,L _(NEW) =ΔL _(DR) ·L _(PRES).  (Equation 15)Accordingly, when operating at the new reduced lighting intensitiesL_(NEW), the lighting loads 112 consume less power. Alternatively, thecontroller 150 may decrease the setpoint light intensity L_(SET) of thespace 160 by a predetermined percentage ΔL_(SET-DR) at step 830.

Next, the controller 150 turns off the designated plug-in electricalloads 142 at step 832. If the HVAC system 132 is presently cooling thebuilding at step 834, the controller 150 increases the setpointtemperatures T_(SET) of each of the temperature control devices 130 by apredetermined increment ΔT_(DR) _(—) _(COOL2) (e.g., approximately 2°F.) at step 836. If the façade 164 of the area may be receiving directsunlight at step 838, the controller 150 controls the motorized rollershade 120 to the fully-closed positions at step 840 in order to reduceheat rise in the area. If the façade 164 of the area is not receivingdirect sunlight at step 838, the controller 150 enables the shadetimeclock schedule at step 842, such that the timeclock executionprocedure 900 will be executed periodically to adjust the positions ofthe motorized roller shades 120 to the controlled positions P_(CNTL)(t)after the demand response control procedure 800 exits.

If the HVAC system 132 is presently heating the building at step 834,the controller 150 decreases the setpoint temperatures T_(SET) of eachof the temperature control devices 130 by a predetermined incrementΔT_(DR) _(—) _(HEAT2) (e.g., approximately 2° F.) at step 844. If thefaçade 164 of the area is not receiving direct sunlight at step 846, thecontroller 150 enables the shade timeclock schedule at step 848, suchthat the timeclock execution procedure 900 will be executed to controlthe positions of the motorized roller shades 120 to the controlledpositions P_(CNTL)(t) after the demand response control procedure 800exits. The controller 150 then enables daylighting monitoring (DM) atstep 850 by initializing a daylighting monitoring (DM) timer (e.g., toapproximately one minute) and starting the timer decreasing in valuewith respect to time. When the daylighting monitoring timer expires, thecontroller 150 will execute a daylighting monitoring (DM) procedure 1000if the daylighting procedure 500 (as shown in FIG. 9) is causing theload control system 100 to save energy. Specifically, the controller 150determines if providing daylight in the area by controlling themotorized roller shades 120 to the controlled positions P_(CNTL)(t) ofthe timeclock schedule has resulted in energy savings in the amount ofenergy consumed by the lighting loads 112 (as compared to the energyconsumed by the lighting loads when the motorized roller shades arefully closed). The daylighting monitoring timer is initialized to anamount of time that is appropriate to allow the lighting control devices110 to adjust the intensities of the lighting loads 112 in response tothe ambient light intensity L_(AMB) measured by the daylight sensor 154.The daylighting monitoring procedure 1000 will be described in greaterdetail below with reference to FIG. 14.

If the façade 164 of the area may be receiving direct sunlight at step846, the controller 150 executes a modified schedule procedure 1100(which will be described in greater detail below with reference to FIG.15A) to temporarily increase the desired maximum sunlight penetrationdistance d_(MAX) by a predetermined amount Δd_(MAX) (e.g., byapproximately 50%) and to generate a modified timeclock schedule at themodified maximum sunlight penetration distance d_(MAX). The controller150 then enables the shade timeclock schedule at step 852, such that thecontroller will adjust the positions of the motorized roller shades 120to the modified controlled positions P_(CNTL)(t) as determined duringthe modified schedule procedure 1100 when the timeclock executionprocedure 900 is executed after the demand response control procedure800 exits. Since the desired maximum sunlight penetration d_(MAX) hasbeen increased, the sunlight will penetrate deeper into the space 160using the modified controlled positions P_(CNTL)(t) determined duringthe modified schedule procedure 1100.

Referring back to FIG. 12B, after executing the modified scheduleprocedure 1100, the controller 150 enables HVAC monitoring at step 854by initializing an HVAC monitoring timer (e.g., to approximately onehour) and starting the timer decreasing in value with respect to time.When the HVAC monitoring timer expires, the controller 150 will executean HVAC monitoring procedure 1150 to determine if the modifiedcontrolled positions P_(CNTL)(t) of the motorized roller shades 120 haveresulted in energy savings in the amount of energy consumed by the HVACsystem 132. The HVAC monitoring procedure 1150 will be described ingreater detail below with reference to FIG. 15B. After enabling HVACmonitoring at step 854, the demand response control procedure 800 exits.

As previously mentioned, the load control procedure 650 is executedperiodically by the controller 150. During the first execution of theload control procedure 650 after a change in state of the load controlsystem 100 (e.g., in response to receiving a demand response command,detecting an occupancy or vacancy condition, or determining that one ofthe façades 164 may be receiving direct sunlight or not), the controller150 is operable to lower the lighting intensities of the lighting loads112 by the predetermined percentage ΔL_(DR) (e.g., at step 830) or toadjust the setpoint temperatures T_(SET) of the temperature controldevices 130 by predetermined amounts (e.g., at steps 724, 728, 818, 822,836, 844). However, during subsequent executions of the load controlprocedure 650, the controller 150 does not continue lowering thelighting intensity of the lighting loads 112 by the predeterminedpercentage ΔL_(DR) (at step 830), or adjusting the setpoint temperaturesT_(SET) by predetermined amounts (at steps 724, 728, 818, 822, 836,844). In addition, the controller 150 only executes the modifiedschedule procedure 1100 and enables daylighting monitoring (at step 850)or HVAC monitoring (at step 854) the first time that the load controlprocedure 650 is executed after a change in state of the load controlsystem 100.

FIG. 13 is a simplified flowchart of the timeclock execution procedure900, which is executed by the controller 150 periodically, i.e., everyminute between the start time t_(START) and the end time t_(END) of theshade timeclock schedule. Since there may be multiple timeclockschedules for the motorized roller shades 120, the controller 150 mayexecute the timeclock execution procedure 900 multiple times, e.g., oncefor each shade timeclock schedule. During the timeclock executionprocedure 900, the controller 150 adjusts the positions of the motorizedroller shades 120 to the controlled positions P_(CNTL)(t) determined inthe timeclock event creation procedure 400 (or alternatively themodified controlled positions P_(CNTL)(t) determined in the modifiedschedule procedure 1100).

In some cases, when the controller 150 controls the motorized rollershades 120 to the fully-open positions P_(FO) (i.e., when there is nodirect sunlight incident on the façade 164), the amount of daylightentering the space 160 (e.g., due to sky luminance from light reflectedoff of clouds or other objects) may be unacceptable to a user of thespace. Therefore, the controller 150 is operable to have a visorposition P_(VISOR) enabled for one or more of the spaces 160 or façades164 of the building. The visor position P_(VISOR) defines the highestposition to which the motorized roller shades 120 will be controlledduring the shade timeclock schedule. The visor position P_(VISOR) istypically lower than the fully-open position P_(FO), but may be equal tothe fully-open position. The position of the visor position P_(VISOR)may be entered using the GUI software of the PC. In addition, the visorposition P_(VISOR) may be enabled and disabled for each of the spaces160 or façades 164 of the building using the GUI software of the PC.

Referring to FIG. 13, if the timeclock schedule is enabled at step 910,the controller 150 determines the time t_(NEXT) of the next timeclockevent from the shade timeclock schedule at step 912. If the present timet_(PRES) (e.g., determined from the astronomical timeclock) is equal tothe next event time t_(NEXT) at step 914 and the controlled positionP_(CNTL)(t_(NEXT)) at the next event time t_(NEXT) is greater than orequal to the visor position P_(VISOR) at step 916, the controller 150sets a new shade position P_(NEW) equal to the visor position P_(VISOR)at step 918. If the controlled position P_(CNTL)(t_(NEXT)) at the nextevent time t_(NEXT) is less than the visor position P_(VISOR) at step916, the controller 150 sets the new shade position P_(NEW) equal to thecontrolled position P_(CNTL)(t_(NEXT)) at the next event time t_(NEXT)at step 920. If the present time t_(PRES) is not equal to the next eventtime t_(NEXT) at step 914, the controller 150 determines the timet_(PREV) of the previous timeclock event from the shade timeclockschedule at step 922 and sets the new shade position P_(NEW) equal tothe controlled position P_(CNTL)(t_(PREV)) at the previous event timet_(PREV) at step 924.

After setting the new shade position P_(NEW) at steps 918, 920, 924, thecontroller 150 makes a determination as to whether the present time isequal to the end time t_(END) of the shade timeclock schedule at step926. If the present time t_(PRES) is equal to the end time t_(END) atstep 926, the controller 150 sets the new shade position P_(NEW) to beequal to the nighttime position P_(NIGHT) at step 928 and disables thetimeclock schedule at step 930. If the new shade position P_(NEW) is thesame as the present shade position P_(PRES) of the motorized rollershades 120 at step 932, the timeclock execution procedure 900 simplyexits without adjusting the positions of the motorized roller shades120. However, if the new shade position P_(NEW) is not equal to thepresent shade position P_(PRES) of the motorized roller shades 120 atstep 932, the controller 150 adjusts the positions of the motorizedroller shades 120 to the new shade position P_(NEW) at step 934 and thetimeclock execution procedure 900 exits.

FIG. 14 is a simplified flowchart of the daylighting monitoringprocedure 1000, which is executed by the controller 150 when thedaylighting monitoring timer expires at step 1010. As previouslymentioned, the daylighting monitoring timer is initialized to an amountof time that is appropriate to allow the lighting control devices 110 toadjust the intensities of the lighting loads 112 in response to theambient light intensity L_(AMB) determined by the daylight sensor 154.During the daylighting monitoring procedure 1000, the controller 150first determines at step 1012 the present intensities of the lightingloads 110 in the area, which are representative of the amount of powerpresently being consumed by the lighting loads. The controller 150compares these lighting intensities to the lighting intensities of thelighting loads 112 that would be required if the motorized roller shades120 were at the fully-closed positions to determine if the load controlsystem 100 is presently saving energy as compared to when the motorizedroller shades 120 are fully closed. If the load control system 100 ispresently saving energy at step 1014, the controller 150 maintains thepresent positions of the motorized roller shades 120 and the daylightingmonitoring procedure 1000 simply exits. However, if the load controlsystem 100 is not presently saving energy at step 1014, the controller150 closes all of the motorized roller shades 120 in the area to reduceheat loss at step 1016, before the daylighting monitoring procedure 1000exits.

FIG. 15A is a simplified flowchart of the modified schedule procedure1100, which is executed by the controller 150 during the demand responsecontrol procedure 800 when the area is occupied, the HVAC system 132 ispresently heating the building, and there may be direct sunlight shiningon the façade 164. First, the controller 150 temporarily increases thedesired maximum sunlight penetration distance d_(MAX) by a predeterminedpercentage Δd_(MAX) (e.g., by approximately 50%) at step 1110, e.g.,d _(MAX)=(1+Δd _(MAX))·d _(MAX).  (Equation 16)Next, the controller 150 executes the optimal shade position procedure300 (as shown in FIG. 5) for determining the optimal shade positionsP_(OPT)(t) of the motorized roller shades 120 in response to themodified desired maximum sunlight penetration distance d_(MAX). Thecontroller 150 then executes the timeclock event creation procedure 400to generate the modified controlled positions P_(CNTL)(t) in response tothe optimal shade positions P_(OPT)(t) determined from the modifieddesired maximum sunlight penetration distance d_(MAX). Finally, themodified schedule procedure 1100 exits.

FIG. 15B is a simplified flowchart of the HVAC monitoring procedure1150, which is executed by the controller 150 when the HVAC monitoringtimer expires at step 1160. The controller 150 first determines energyusage information from the HVAC system 132. For example, the controller150 could cause the temperature control device 130 to transmit a requestfor energy usage information from the HVAC system 132 via the HVACcommunication link 134. Alternatively, the temperature control device130 could store data representative of the energy usage information ofthe HVAC system 132. For example, the temperature control device 130could monitor when the HVAC system 132 is active or inactive whileoperating to heat the building when HVAC monitoring in enabled anddetermine a heating duty cycle, which is representative of the energyusage information of the HVAC system 132. Alternatively, the temperaturecontrol device 130 could monitor the rate at which the temperature inthe space 160 decreases when the HVAC system is not actively heating thespace.

Referring back to FIG. 15B, the controller 150 determines if the HVACsystem 132 is saving energy during the HVAC monitoring at step 1164. Forexample, the controller 150 could compare the heating duty cycle duringHVAC monitoring to the heating duty cycle prior to HVAC monitoring todetermine if the HVAC system 132 is saving energy. If the heating dutycycle during HVAC monitoring is less than the heating duty cycle priorto HVAC monitoring than the HVAC system is saving energy. Alternatively,the controller 150 could compare the rate at which the presenttemperature T_(PRES) of the space 160 decreases when the HVAC system 132is not actively heating the space during HVAC monitoring to the rateprior to HVAC monitoring to determine if the HVAC system is savingenergy. If the rate at which the present temperature T_(PRES) of thespace 160 decreases when the HVAC system 132 is not actively heating thespace 160 is less than the rate prior to HVAC monitoring, the HVACsystem is saving energy. If the controller 150 determines that the HVACsystem 132 is saving energy at step 1164, the controller 150 maintainsthe present positions of the motorized roller shades 120 and the HVACmonitoring procedure 1150 simply exits. However, if the HVAC system 132is not presently saving energy at step 1164, the controller 150 closesall of the motorized roller shades 120 in the area to reduce heat lossat step 1166, before the HVAC monitoring procedure 1150 exits.Alternatively, the HVAC monitoring procedure 1150 could be executed bythe temperature control device 130.

FIG. 16 is a simplified flowchart of a planned demand response procedure1200 executed by the controller 150 of the load control system 100according to a second embodiment of the present invention. In responseto receiving a planned demand response command, the controller 150controls the load control system 100 to reduce the total powerconsumption at a predetermined start time t_(START) in the future, forexample, at noon on the day after the planned demand response commandwas received. The controller 150 is operable to “pre-condition” (i.e.,pre-cool or pre-heat) the building before the start time t_(START) ofthe planned demand response command, such that the HVAC system 132 willbe able to consume less power during the planned demand response event(i.e., after the start time). To pre-condition the building before aplanned demand response event, the controller 150 is operable topre-cool the building when the HVAC system 132 is in the cooling modeand will be cooling the building during the present day (e.g., duringthe summer), and to pre-heat the building when the HVAC system is inheating mode and the will be heating the building during the present day(e.g., during the winter).

Referring to FIG. 16, the planned demand response procedure 1200 isexecuted by the controller 150 when a planned demand response command isreceived via the network communication link 156 at step 1210. Thecontroller 150 first determines if the present time of the day is beforethe predetermined pre-condition time t_(PRE) (e.g., approximately 6A.M.) at step 1212. If so, the controller 150 enables a pre-conditiontimeclock event at step 1214. The controller 150 will then execute (inthe future at the pre-condition time t_(PRE)) a pre-condition timeclockevent procedure 1300, which will be described in greater detail belowwith reference to FIG. 17. If the present time of the day is after thepre-condition time t_(PRE) at step 1212 and the HVAC system 132 ispresently cooling the building at step 1216, the controller 150decreases the setpoint temperatures T_(SET) of each of the temperaturecontrol devices 130 in the building by a pre-cool temperature incrementΔT_(PRE-COOL) (e.g., approximately 4° F.) at step 1218 in order topre-condition the building before the planned demand response event.Specifically, the setpoint temperature T_(SET) of the building islowered from an initial temperature T_(INIT) to a new temperatureT_(NEW) to pre-cool the building in preparation for the planned demandresponse event during which the setpoint temperature will be increasedabove the initial temperature T_(INIT) (as will be described in greaterdetail below with reference to FIG. 18).

Referring back to FIG. 16, if the HVAC system 132 is presently heatingthe building at step 1216, the controller 150 increases the setpointtemperatures T_(SET) of each of the temperature control devices 130 inthe building by a pre-heat temperature increment ΔT_(PRE-HEAT) (e.g.,approximately 4° F.) at step 1220. After either enabling thepre-condition timeclock event at step 1214 or pre-conditioning thebuilding at step 1218 or step 1220, the controller 150 enables a planneddemand response timeclock event at step 1222, before the planned demandresponse procedure 1200 exits. A planned demand response timeclock eventprocedure 1400 will be executed by the controller 150 at a planneddemand response start time t_(START). The planned demand responsetimeclock event procedure 1400 will be described in greater detail belowwith reference to FIG. 18.

FIG. 17 is a simplified flowchart of the pre-condition timeclock eventprocedure 1300, which is executed by the controller 150 at step 1310(i.e., at the pre-condition time t_(PRE)). If the pre-conditiontimeclock event is not enabled at step 1312, the pre-condition timeclockevent procedure 1300 simply exits. However, if the pre-conditiontimeclock event is enabled at step 1312 and the HVAC system 132 ispresently cooling the building at step 1314, the controller 150 causeseach of the temperature control devices 130 to decrease the setpointtemperatures T_(SET) by the pre-cool temperature increment ΔT_(PRE-COOL)(i.e., approximately 4° F.) at step 1316 in order to pre-cool thebuilding before the planned demand response event, and the pre-conditiontimeclock event procedure 1300 exits. If the HVAC system 132 ispresently heating the building at step 1314, the controller 150increases the setpoint temperatures T_(SET) of each of the temperaturecontrol devices 130 by the pre-heat temperature increment ΔT_(PRE-HEAT)(e.g., approximately 4° F.) at step 1318 in order to pre-heat thebuilding before the planned demand response event, and the pre-conditiontimeclock event procedure 1300 exits.

FIG. 18 is a simplified flowchart of the planned demand responsetimeclock event procedure 1400, which is executed by the controller 150at step 1410 (i.e., at the start time t_(START)). If the planned demandresponse timeclock event is not enabled at step 1412, the planned demandresponse timeclock event procedure 1400 simply exits. However, if theplanned demand response timeclock event is enabled at step 1412 and theHVAC system 132 is presently cooling the building at step 1414, thecontroller 150 causes each of the temperature control devices 130 toincrease the respective setpoint temperature T_(SET) by a temperatureincrement ΔT_(PLAN1) (i.e., approximately 8° F.) at step 1416, such thatthe new temperature T_(NEW) is greater than the initial temperatureT_(INIT) of the building before pre-cooling, i.e.,T _(NEW) =T _(INIT)+(ΔT _(PLAN1) −ΔT _(PRE-COOL)).  (Equation 17)At step 1418, the controller 150 causes the lighting control devices 110to lower each of the present lighting intensities L_(PRES) of thelighting loads 112 by a predetermined percentage ΔL_(PLAN1) (e.g., byapproximately 20% of the present intensity), such that the lightingloads consume less power. At step 1420, the controller 150 causes eachof the motorized roller shades 120 to move the respective shade fabric122 to the fully-closed position, before the planned demand responsetimeclock event procedure 1400 exits.

If the HVAC system 132 is presently heating the building at step 1414,the controller 150 decreases the setpoint temperatures T_(SET) of eachof the temperature control devices 130 by a temperature incrementΔT_(PLAN2) (i.e., approximately 8° F.) at step 1422, such that the newtemperature T_(NEW) is less than the initial temperature T_(INIT) of thebuilding before pre-heating, i.e.,T _(NEW) =T _(INIT)−(ΔT _(PLAN2) −ΔT _(PRE-HEAT)).  (Equation 18)At step 1424, the controller 150 decreases each of the present lightingintensities L_(PRES) of the lighting loads 112 connected to the lightingcontrol devices 110 by a predetermined percentage ΔL_(PLAN2) (e.g., byapproximately 20% of the present intensity). At step 1426, thecontroller 150 moves the respective shade fabric 122 of each of themotorized roller shades 120 to the fully-closed position, before theplanned demand response timeclock event procedure 1400 exits.

While the controller 150 of the load control system 100 of FIG. 1receives the demand response command from the electrical utility companyvia the network communication link 156, the load control system couldalternatively receive the demand response command through other means.Often, the electrical utility company may not be connected to the loadcontrol system 100 via the Internet (i.e., via the network communicationlink 156). In such situations, a representative of the electricalutility company may contact a building manager of the building in whichthe load control system 100 is installed via telephone in order tocommunicate the specific demand response command. For example, thebuilding manager could actuate one of the buttons 114 on the lightingcontrol device 110 in order to input an immediate demand responsecommand to the load control system 100. The lighting control device 110could then transmit appropriate digital messages to the controller 150.Alternatively, the load control system 100 could also comprise apersonal computer or laptop operable to communicate with the controller150. The building manager could use the personal computer to communicatean immediate or a planned demand response command to the controller 150.Further, the controller 150 could include an antenna, such that thebuilding manager could use a wireless cell phone or a wireless personaldigital assistant (PDA) to transmit an immediate or a planned demandresponse command wirelessly to the controller (e.g., via RF signals).

According to a third embodiment of the present invention, the controller150 is operable to control the lighting control device 110, themotorized roller shades 120, the temperature control device 130, and thecontrollable electrical receptacle 140 according to a plurality ofdemand response (DR) levels. A demand response level is defined as acombination of predetermined parameters (e.g., lighting intensities,shades positions, temperatures, etc.) for one or more of the loads ofthe load control system 100. The demand response levels provide a numberof predetermined levels of energy savings that the load control system100 may provide in response to the demand response command. For example,in a specific demand response level, a certain number of lighting loadsmay be dimmed by a predetermined amount, a certain number of motorizedroller shades may be closed, a certain number of plug-in electricalloads 142 may be turned off, and the setpoint temperature may beadjusted by a certain amount. The demand response level to which thecontroller 150 controls the load control system 100 may be included inthe demand response command received from the electrical utility companyvia the network communication link 156. Alternatively, the demandresponse command received from the electrical utility company may notinclude a specific demand response level. Rather, the controller 150 maybe operable to select the appropriate demand response level in responseto the demand response command transmitted by the electrical utilitycompany.

When the load control system 100 is programmed to provide multipledemand response levels, each successive demand response level furtherreduces the total power consumption of the load control system 100. Forexample, the electrical utility company may first transmit a demandresponse command having demand response level one to provide a firstlevel of energy savings, and then may subsequently transmit demandresponse commands having demand response levels two, three, and four tofurther and sequentially reduce the total power consumption of the loadcontrol system 100. Four example demand response levels are provided inthe following table, although additional demand response levels could beprovided. As shown in Table 1, the second demand response level causesthe load control system 100 to consume less power than the first demandresponse level, and so on.

TABLE 1 Example Demand Response (DR) Levels of the Third Embodiment LoadMotorized Roller Temperature Plug-In DR Level Lighting Loads Shades(HVAC) Electrical Loads DR Level 1 Reduce intensities Close shades inIncrease/reduce No change. of lighting loads in some areas. temperatureby 2° F. some areas by 20%. when heating and cooling. DR Level 2 Reduceintensities Close shades in Increase/reduce No change. of lighting loadsin all areas. temperature by 4° F. all areas by 20%. when heating andcooling. DR Level 3 Reduce intensities Close shades in Increase/reduceNo change. of lighting loads in all areas. temperature by 6° F. allareas by 50%. when heating and cooling. DR Level 4 Reduce intensitiesClose shades in Turn off HVAC Turn off some of lighting loads in allareas. system when cooling plug-in all areas by 50%. or reducetemperature electrical loads. to 45° F. when heating.

FIGS. 19A and 19B are simplified flowcharts of a demand response levelprocedure 1500 executed by the controller 150 according to the thirdembodiment of the present invention. The demand response level procedure1500 is executed by the controller 150 in response to receiving a demandresponse command including a demand response level via the networkcommunication link 156 at step 1510. If the demand response level of thereceived demand response command is one at step 1512, the controller 150lowers the present intensities L_(PRES) of only some of the lightingloads 112, for example, only the lighting loads 112 in the non-workingareas of the building (such as, for example, rest rooms, corridors, andpublic areas) by a first predetermined percentage ΔL₁ (e.g.,approximately 20% of an initial lighting intensity L_(INIT)) at step1514. The controller 150 then closes the motorized roller shades 120 inthe same non-working areas of the building at step 1516. If the HVACsystem 132 is presently cooling the building at step 1518, thecontroller 150 increases the setpoint temperatures T_(SET) by a firsttemperature increment ΔT₁ (e.g., approximately 2° F.) at step 1520, andthe demand response level procedure 1500 exits. If the HVAC system 132is presently heating the building at step 1518, the controller 150decreases the setpoint temperatures T_(SET) by the first temperatureincrement ΔT₁ at step 1522, and the demand response level procedure 1500exits.

If the demand response level of the received demand response command isnot one at step 1512, but is two at step 1524, the controller 150 lowersthe present intensities L_(PRES) of all of the lighting loads 112 in thebuilding, i.e., including the working areas of the building (such as,office spaces and conference rooms) by the first predeterminedpercentage ΔL₁ (i.e., approximately 20% of the initial lightingintensity L_(INIT)) at step 1526. If the controller 150 had previouslyreduced the present intensities L_(PRES) of the lighting loads 112 inthe non-working areas of the building at step 1514 (i.e., according tothe demand response level one), the controller only adjusts the presentintensities L_(PRES) of the lighting loads 112 in the working areas ofthe building at step 1526. At step 1528, the controller 150 then closesthe motorized roller shades 120 in all of the areas of the building. Ifthe HVAC system 132 is presently cooling the building at step 1530, thecontroller 150 increases the setpoint temperature T_(SET) by a secondtemperature increment ΔT₂ (e.g., approximately 4° F.) at step 1532, andthe demand response level procedure 1500 exits. If the controller 150had previously increased the setpoint temperatures T_(SET) by the firsttemperature increment ΔT₁ at step 1520 (i.e., according to the demandresponse level one), the controller 150 only increases the setpointtemperatures T_(SET) by approximately 2° F. at step 1532, (i.e.,ΔT₂−ΔT₁). If the HVAC system 132 is presently heating the building atstep 1530, the controller 150 decreases the setpoint temperature T_(SET)by the second temperature increment ΔT₂ at step 1534, and the demandresponse level procedure 1500 exits.

Referring to FIG. 19B, if the demand response level is not two at step1524, but is three at step 1536, the controller 150 lowers the presentintensities L_(PRES) of all of the lighting loads 112 in the building bya second predetermined percentage ΔL₂ (i.e., approximately 50% of theinitial lighting intensity L_(INIT)) at step 1538. If the controller 150had previously reduced the present intensities L_(PRES) of the lightingloads 112 in any of the areas of the building at steps 1514 or 1526(i.e., according to the demand response levels one or two), thecontroller only adjusts the present intensities L_(PRES) of each of thelighting loads 112 by the necessary amount at step 1538. The controller150 then closes the motorized roller shades 120 in all of the areas ofthe building at step 1540 (if needed). If the HVAC system 132 ispresently cooling the building at step 1542, the controller 150increases the setpoint temperature T_(SET) by a third temperatureincrement ΔT₃ (e.g., approximately 6° F.) at step 1544, and the demandresponse level procedure 1500 exits. If the HVAC system 132 is presentlyheating the building at step 1542, the controller 150 decreases each ofthe setpoint temperatures T_(SET) by the third temperature increment ΔT₃at step 1546, and the demand response level procedure 1500 exits.

If the demand response level is not three at step 1536, but is four atstep 1548, the controller 150 lowers the present intensities L_(PRES) ofall of the lighting loads 112 in the building by the secondpredetermined percentage ΔL₂ at step 1550 (if needed) and closes all ofthe motorized roller shades 120 at step 1552 (if needed). At step 1554,the controller 150 transmits digital messages to the electricalreceptacles 140 to turn off the designated plug-in electrical loads 142,such as, for example, table lamps, floor lamps, printers, fax machines,water heaters, water coolers, and coffee makers, but leaves some otherplug-in loads powered, such as, personal computers. If the HVAC system132 is presently cooling the building at step 1556, the controller 150turns off the HVAC system at step 558, and the demand response levelprocedure 1500 exits. If the HVAC system 132 is presently heating thebuilding at step 1556, the controller 150 causes each of the temperaturecontrol devices 130 to decrease the respective setpoint temperatureT_(SET) to a minimum temperature T_(MIN) at step 1560 and the demandresponse level procedure 1500 exits.

FIG. 20 is a simplified block diagram of a distributed load controlsystem that may be installed in a building, such as a residence,according to a fourth embodiment of the present invention. The loadcontrol system 1600 comprises a lighting control device, e.g., awall-mountable dimmer switch 1610, which is coupled to an AC powersource 1602 via a line voltage wiring 1604. The dimmer switch 1610 isoperable to adjust the amount of power delivered to the lighting load1612 to thus control the present lighting intensity L_(PRES) of thelighting load 1612. The dimmer switch 1610 is also operable to fade thepresent lighting intensity L_(PRES) between two lighting intensities.The dimmer switch 1610 comprises a control actuator 1614 for allowing auser to turn the lighting load 1612 on and off. The dimmer switch 1610further comprises an intensity adjustment actuator 1616 for allowing theuser to adjust the present lighting intensity L_(PRES) of the lightingload 1612 between a minimum lighting intensity L_(MIN) and a maximumlighting intensity L_(MAX). An example of a wall-mountable dimmer switchis described in greater detail in previously-referenced U.S. Pat. No.5,248,919.

The dimmer switch 1610 is operable to transmit and receive digitalmessages via wireless signals, e.g., RF signals 1606 (i.e., an RFcommunication link). The dimmer switch 1610 is operable to adjust thepresent lighting intensity L_(PRES) of the lighting load 1612 inresponse to the digital messages received via the RF signals 1606. Thedimmer switch 1610 may also transmit feedback information regarding theamount of power being delivered to the lighting load 1610 via thedigital messages included in the RF signals 1606. Examples of RFlighting control systems are described in greater detail incommonly-assigned U.S. Pat. No. 5,905,442, issued on May 18, 1999,entitled METHOD AND APPARATUS FOR CONTROLLING AND DETERMINING THE STATUSOF ELECTRICAL DEVICES FROM REMOTE LOCATIONS, and U.S. patent applicationSer. No. 12/033,223, filed Feb. 19, 2008, entitled COMMUNICATIONPROTOCOL FOR A RADIO-FREQUENCY LOAD CONTROL SYSTEM, the entiredisclosures of which are both hereby incorporated by reference.

The load control system 1600 comprises a motorized window treatment,e.g., a motorized roller shade 1620, which may be positioned in front ofa window for controlling the amount of daylight entering the building.The motorized roller shade 1620 comprises a flexible shade fabric 1622rotatably supported by a roller tube 1624, and an electronic drive unit(EDU) 1626, which may be located inside the roller tube 1624. Theelectronic drive unit 1626 may be powered by an external transformer(XFMR) 1628, which is coupled to the AC power source 1602 and produces alower voltage AC supply voltage for the electronic drive unit. Theelectronic drive unit 1626 is operable to transmit and receive the RFsignals 1606, such that the electronic drive unit may control theposition of the shade fabric 1622 in response to digital messagesreceived via the RF signals and may transmit feedback informationregarding the position of the shade fabric via the RF signals.

The load control system 1600 also comprises a temperature control device1630, which is coupled to an HVAC system 1632 via an HVAC communicationlink 1634, e.g., a digital communication link, such as an Ethernet link.The temperature control device 1630 measures the present temperatureT_(PRES) in the building and transmits appropriate digital messages tothe HVAC system 1632 to thus control the present temperature T_(PRES) inthe building towards the setpoint temperature T_(SET). The temperaturecontrol device 1630 is operable to adjust the setpoint temperatureT_(SET) in response to the digital messages received via the RF signals1606. Alternatively, the HVAC communication link 1634 could comprise amore traditional analog control link for simply turning the HVAC system1632 on and off.

FIG. 21A is an enlarged front view of the temperature control device1630. The temperature control device 1630 comprises a temperatureadjustment actuator 1670 (e.g., a rocker switch). Actuations of an upperportion 1670A of the temperature adjustment actuator 1670 cause thetemperature control device 1630 to increase the setpoint temperatureT_(SET), while actuations of a lower portion 1670B of the temperatureadjustment actuator cause the temperature control device to decrease thesetpoint temperature T_(SET). The temperature control device 1630further comprises a room temperature visual display 1672A and a setpointtemperature visual display 1672B, which each comprise linear arrays oflight-emitting diodes (LEDs) arranged parallel to each other as shown inFIG. 21A. One of the individual LEDs of the room temperature visualdisplay 1672A is illuminated to display the present temperature T_(PRES)of the room in which the temperature control device 1630 is located, forexample, on a linear scale between 60° F. and 80° F. In a similarmanner, one of the individual LEDs of the setpoint temperature visualdisplay 1672B is illuminated to display the setpoint temperature T_(SET)of the temperature control device 1630. The temperature control device1630 transmits digital messages to the other control devices of the loadcontrol system 1600 via the RF signals 1606 in response to actuations ofan “eco-saver” actuator 1674 as will be described below. The temperaturecontrol device 1630 has a cover plate 1676, which covers a plurality ofoperational actuators 1678. FIG. 21B is a front view of the temperaturecontrol device 1630 in which the cover plate 1676 is open and theoperational actuators 1678 are shown. Actuations of the operationalactuators 1678 adjust the operation of the HVAC system 1632, forexample, to change between the heating mode and the cooling mode.

Referring back to FIG. 20, the load control system 1600 may alsocomprise a wireless temperature sensor 1636, which may be mountedremotely in a location away from the temperature control device 1630 andmay also be battery-powered. FIG. 22 is an enlarged perspective view ofthe wireless temperature sensor 1636. The wireless temperature sensor1636 comprises an internal temperature sensing device (not shown) formeasuring the present temperature T_(PRES) in the building at thelocation away from the temperature control device 1630. The wirelesstemperature sensor 1636 comprises vents 1680, which allow for air flowfrom the outside of the temperature sensor to the internal temperaturesensing device inside the temperature sensor. The vents 1680 help toimprove the accuracy of the measurement of the present temperatureT_(PRES) in the room in which the wireless temperature sensor 1636 ismounted (i.e., of the temperature outside the wireless temperaturesensor). The wireless temperature sensor 1636 further comprises a linkbutton 1682 and a test button 1684 for use during setup andconfiguration of the wireless temperature sensor. The wirelesstemperature sensor 1636 is operable to transmit digital messagesregarding the measured temperature to the temperature control device1630 via the RF signals 1606. In response to receiving the RF signals1606 from the wireless temperature sensor 1636, the temperature controldevice is operable to update the room temperature visual display 1672Ato display the present temperature T_(PRES) of the room at the locationof the wireless temperature sensor and to control the HVAC system 1632,so as to move the present temperature T_(PRES) in the room towards thesetpoint temperature T_(SET).

FIG. 23 is a simplified block diagram of the temperature control device1630. The temperature control device 1630 comprises a controller 1690,which may be implemented as, for example, a microprocessor, amicrocontroller, a programmable logic device (PLD), an applicationspecific integrated circuit (ASIC), or any suitable processing device.The controller 1692 is coupled to an HVAC communication circuit 1692(e.g., a digital communication circuit, such as an Ethernetcommunication circuit), which is connected to the HVAC communicationlink 1634 to allow the controller to adjust the setpoint temperatureT_(SET) of the HVAC system 1632. If the HVAC communication circuit 1692comprises an analog control link, the HVAC communication circuit 1692could simply comprise a switching device for enabling and disabling theHVAC system 1632.

The controller 1690 is operable to determine the present temperatureT_(PRES) in the building in response to an internal temperature sensor1694. The controller 1690 is further coupled to a wireless communicationcircuit, e.g., an RF transceiver 1695, which is coupled to an antenna1696 for transmitting and receiving the RF signals 1606. The controller1690 is operable to determine the present temperature T_(PRES) in thebuilding in response to the RF signals 1606 received from the wirelesstemperature sensor 1636. Alternatively, the temperature control device1630 may simply comprise either one or the other of the internaltemperature sensor 1694 and the RF transceiver 1695 for determining thepresent temperature T_(PRES) in the room. Examples of antennas forwall-mounted control devices are described in greater detail incommonly-assigned U.S. Pat. No. 5,982,103, issued Nov. 9, 1999, and U.S.Pat. No. 7,362,285, issued Apr. 22, 2008, both entitled COMPACT RADIOFREQUENCY TRANSMITTING AND RECEIVING ANTENNA AND CONTROL DEVICEEMPLOYING SAME, the entire disclosures of which are hereby incorporatedby reference.

The temperature control device 1630 further comprises to a memory 1698for storage of the setpoint temperature T_(SET) and the presenttemperature T_(PRES) in the building, as well as data representative ofthe energy usage information of the HVAC system 1632. The memory 1698may be implemented as an external integrated circuit (IC) or as aninternal circuit of the controller 1690. The controller 1690 may beoperable to determine the data representative of the energy usageinformation of the HVAC system 1632 in a similar manner as thetemperature control device 130 of the first embodiment. For example, thedata representative of the energy usage information of the HVAC system1632 may comprise values of the duty cycle defining when the HVAC systemis active and inactive during a predetermined time period, or the rateat which the present temperature T_(PRES) decreases or increases in theroom when the HVAC system is not actively heating or cooling the space,respectively, during a predetermined time period.

A power supply 1699 receives power from the line voltage wiring 1604 andgenerates a DC supply voltage V_(CC) for powering the controller 1690and other low-voltage circuitry of the temperature control device 1630.The controller 1690 is coupled to the temperature adjustment actuator1670, the eco-saver actuator 1674, and the operational actuators 1678,such that the controller is operable to adjust the operation of the HVACsystem 1632 in response to actuations of these actuators. The controller1690 is coupled to the room temperature visual display 1672A and thesetpoint temperature visual display 1672B for displaying the presenttemperature T_(PRES) and the setpoint temperature T_(SET), respectively.

Referring back to FIG. 20, the load control system 100 further comprisesone or more controllable electrical receptacles 1640, and plug-in loadcontrol devices 1642 for control of plug-in electrical loads, such as,for example, a table lamp 1644, a television 1646, a floor lamp, astereo, or a plug-in air conditioner. The controllable electricalreceptacle 1640 and the plug-in load control device 1642 are responsiveto the digital messages received via the RF signals 1606 to turn on andoff the respective plug-in loads 1644, 1646. The plug-in load controldevice 1642 is adapted to be plugged into a standard electricalreceptacle 1648. The controllable electrical receptacle 1640 maycomprise a dimmable electrical receptacle including an internal dimmingcircuit for adjusting the intensity of the lamp 1644. Additionally, theload control system 1600 could comprise one or more controllable circuitbreakers (not shown) for control of other switched electrical loads,such as, for example, a water heater. The load control system 1600 mayalso comprise additional dimmer switches 1610, motorized roller shades1620, temperature control devices 1630, controllable electricalreceptacles 1640, and plug-in load control devices 1642.

According to the fourth embodiment of the present invention, the dimmerswitch 1610, the motorized roller shade 1620, the temperature controldevice 1630, and the controllable electrical receptacles 1640, 1642 areeach individually responsive to a plurality of demand response levels,i.e., predetermined energy-savings “presets”. The energy-savings presetsmay be user selectable and may be defined to provide energy savings fordifferent occupancy conditions of the building. For example, theenergy-savings presets may comprise a “normal” preset, an “eco-saver”preset, an “away” preset, a “vacation” preset, and a “demand response”preset. Examples of the energy-savings presets are provided in thefollowing table.

TABLE 2 Example Energy-Savings Presets of the Fourth Embodiment LoadMotorized Roller Temperature Plug-In Preset Lighting Loads Shades (HVAC)Electrical Loads Normal Reduce intensities Shade positions asTemperature as No change. of lighting loads controlled by user.controlled by user. by 0%. Eco-Saver Reduce intensities Control positionin Increase/reduce No change. of lighting loads response to ambienttemperature by 2° F. by 15%. light intensity. when heating and cooling.Away Turn off all Close all shades. Increase/reduce Turn off lamps,lighting loads. temperature by 6° F. television, and when heating andstereo. cooling. Vacation Turn off all Close all shades. Increase temp.by Turn off lamps, lighting loads. 10° F. when cooling television, orreduce temp. to stereo, and water 45° F. when heating. heater. DemandReduce intensities Close all shades. Increase/reduce No change. Responseof lighting loads temperature by 2° F. by 20%. when heating and cooling.

When the normal preset is selected, the load control system 1600operates as controlled by the occupant of the building, i.e., the normalpreset provides no changes to the parameters of the load control system.For example, the lighting loads 1612 may be controlled to 100%, themotorized roller shades 1620 may be opened, and the setpoint temperatureT_(SET) may be controlled to any temperature as determined by theoccupant. The eco-saver preset provides some energy savings over thenormal preset, but still provides a comfortable environment for theoccupant. The away preset provides additional energy savings by turningoff the lighting loads and some of the plug-in electrical loads when theoccupant may be away temporarily away from the building. The vacationpreset provides the maximum energy savings of the energy-savings presetsshown in Table 2 for times when the occupant may be away from thebuilding for an extended period of time.

The temperature control device 1630 is operable to increase or decreasethe setpoint temperature T_(SET) in response to the mode of the HVACsystem 1632 (i.e., heating or cooling, respectively) as part of theenergy-savings presets. The temperature control device 1630 may comprisea heating and cooling switch for changing between heating and cooling ofthe building. Alternatively, the temperature control device 1630 could,as part of the energy-savings presets, adjust the setpoint temperatureT_(SET) in response the present time of the year (i.e., the summer orthe winter). For example, the lighting control device 1610 couldcomprise an astronomical time clock and may transmit digital messagesincluding the present time of the year via the RF signals 1606.

The load control system 1600 may also include a keypad 1650 to allow formanual selection of the energy-savings presets, specifically, the normalpreset, the eco-saver preset, the away preset, and the vacation preset.The keypad 1650 comprises a plurality of preset buttons 1652 including,for example, a preset button 1652 for each of the energy-savings presetsthat may be selected by the keypad 1650. The keypad 1650 transmitsdigital messages to the other control devices of the load control system1600 via the RF signals 1606 in response to actuations of the presetbuttons 1652. The dimmer switch 1610, the motorized roller shade 1620,the temperature control device 1630, the controllable electricalreceptacles 1640, and the plug-in load control device 1642 operate asshown in Table 2 in response to the specific energy-savings presettransmitted in the digital messages from the keypad 1650. In addition,the eco-saver preset may be selected in response to an actuation of theeco-saver actuator 1674 on the temperature control device 1630.Specifically, the controller 1690 of the temperature control device 1630is operable to transmit a digital message including an eco-saver presetcommand via the RF transceiver 1695 in response to an actuation of theeco-saver actuator 1674.

The load control system 1600 may also comprise a smart power meter 1660coupled to the line voltage wiring 1604. The smart power meter 1660 isoperable to receive demand response commands from the electrical utilitycompany, for example, via the Internet or via RF signals. The smartpower meter 1660 may be operable to wirelessly transmit a digitalmessage including the received demand response command to a demandresponse orchestrating device 1662, which may be, for example, pluggedinto a standard electrical receptacle 1649. In response to receiving adigital message from the smart power meter 1660, the demand responseorchestrating device 1662 is operable to subsequently transmit digitalmessages including, for example, the demand response preset, via the RFsignals 1606 to the dimmer switch 1610, the motorized roller shade 1620,the temperature control device 1630, the controllable electricalreceptacle 1640, and the plug-in load control device 1642. Accordingly,as shown by the example data in Table 1, the dimmer switch 1610 reducesthe present lighting intensity L_(PRES) of the lighting load 1612 by 20%and the electronic drive units 1626 move the respective shade fabrics1622 to the fully-closed position in response to receiving the demandresponse command. In response to receiving the utility-company command,the temperature control device 1630 also increases the setpointtemperature T_(SET) by 2° F. when the HVAC system 1632 is presently inthe cooling mode, and decreases the setpoint temperature T_(SET) by 2°F. when the HVAC system 1632 is presently in the heating mode. Inaddition, the demand response orchestrating device 1662 may comprise oneor more buttons 1664 for selecting the energy-savings presets.Alternatively, the smart power meter 1660 may be operable to wirelesslytransmit digital message directly to the dimmer switch 1610, themotorized roller shade 1620, the temperature control device 1630, thecontrollable electrical receptacle 1640, and the plug-in load controldevice 1642.

The load control system 1600 may further comprise a wireless occupancysensor 1668. The occupancy sensor 1668 is operable to wirelesslytransmit digital messages to the dimmer switch 1610, the motorizedroller shade 1620, the temperature control device 1630, the controllableelectrical receptacles 1640, and the plug-in load control device 1642 inresponse to detecting an occupancy condition or a vacancy condition inthe space in which the occupancy sensor in mounted. For example, thedimmer switch 1610, the motorized roller shade 1620, the temperaturecontrol device 1630, the controllable electrical receptacles 1640, andthe plug-in load control device 1642 operate according to the awaypreset in response a vacancy condition, and according to the normalpreset in response to an occupied condition.

The load control system 1600 may further comprise a wireless daylightsensor 1669 for measuring the ambient light intensity L_(AMB) in theroom in which the daylight sensor is mounted. The daylight sensor 1669is operable to wirelessly transmit digital messages to the dimmer switch1610, the motorized roller shade 1620, the temperature control device1630, the controllable electrical receptacles 1640, and the plug-in loadcontrol device 1642 in response to the ambient light intensity L_(AMB)in the space in which the daylight sensor in mounted. The motorizedroller shade 1620 may be operable to control the position of the shadefabric 1622 in response to amount of daylight entering the buildingthrough the window as part of the eco-saver preset. In addition, themotorized roller shade 1620 could control the position of the shadefabric 1622 in response to the present time of the year and the presenttime of the day as part of the eco-saver preset.

According to another embodiment of the present invention, afterreceiving a demand response preset, the temperature control device 1630is operable to transmit RF signals 1606 to the control devices of theload control system 1600 in response to the data representative of theenergy usage information of the HVAC system 1632 stored in the memory1698. For example, the controller 1690 of the temperature control device1630 may be operable to execute an HVAC monitoring procedure similar tothe HVAC monitoring procedure 1150 shown in FIG. 15B to control themotorized roller shade 1620 in dependence upon the data representativeof the energy usage information of the HVAC system 1632. The controller1690 is operable to monitor the operation of the HVAC system 1632 forthe predetermined time period (e.g., approximately one hour) after themotorized roller shade 1620 moves the shade fabric 1622 in a firstdirection from an initial position, and to determine if the HVAC system1632 is consuming more energy than when the shade fabric was in theinitial position (i.e., if the heating and cooling system is consumingmore energy at the end of the predetermined time period than at thebeginning of the predetermined time period). The controller 1690 is thenoperable to transmit a digital message to the motorized roller shade1620, such that the motorized roller shade moves the shade fabric 1622in a second direction opposite the first direction if the HVAC system1632 is consuming more energy than when the shade fabric was in theinitial position.

Specifically, in response to receiving a demand response preset, themotorized roller shade 1620 is operable to open the shade fabric 1622from the initial position to allow more sunlight to enter the room whenthe HVAC system 1632 is heating the building, to thus attempt to warmthe room using daylight. If the controller 1690 of the temperaturecontrol device 1630 then determines that the HVAC system 1632 is notsubsequently saving energy, the controller may transmit a digitalmessage including a command to close the shade fabric 1622 (e.g., to thefully-closed position) directly to the motorized roller shade 1620 viathe RF transceiver 1695. Similarly, when the HVAC system 1632 is coolingthe building, the motorized roller shade 1620 could close the shadefabric 1622 from the initial position to allow less sunlight to enterthe room, and open the shade fabric (e.g., to the fully-open position)if the HVAC system is not subsequently saving energy. Alternatively, thecontroller 1690 of the temperature control device 1630 could simplytransmit the data representative of the energy usage information of theHVAC system 1632 to the motorized roller shade 1620, and the motorizedroller shade could response appropriately to the data representative ofthe energy usage information of the HVAC system.

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art. It ispreferred, therefore, that the present invention be limited not by thespecific disclosure herein, but only by the appended claims.

What is claimed is:
 1. A load control system for use in a buildinghaving a heating and cooling system and a window located in a space ofthe building, the load control system comprising: a temperature controldevice for controlling a setpoint temperature of the heating and coolingsystem to thus control a present temperature in the building; and amotorized window treatment for controlling a window treatment coveringto an initial position between a fully open position in which the windowis not covered and a fully-closed position in which the window iscovered; wherein after the motorized window treatment moves the coveringin a first direction from the initial position towards the fully openposition to allow more sunlight to enter the space when the heating andcooling system is heating the building, the load control systemdetermines if the heating and cooling system is consuming more energythan when the covering was in the initial position; and wherein if theheating and cooling system is consuming more energy than when thecovering was in the initial position, the motorized window treatmentmoves the covering in a second direction towards the fully-closedposition.
 2. The load control system of claim 1, wherein the loadcontrol system is responsive to a demand response command.
 3. The loadcontrol system of claim 2, wherein the motorized window treatment movesthe covering in the first direction in response to the demand responsecommand when a calculated position of the sun indicates that there isdirect sunlight on the window.
 4. The load control system of claim 3,wherein the motorized window treatment opens the covering from theinitial position to allow more sunlight to enter the space in responseto the demand response command when the heating and cooling system isheating the building, the motorized window treatment closing thecovering if the heating and cooling system is consuming more energy thanwhen the covering was in the initial position.
 5. The load controlsystem of claim 4, wherein, if the heating and cooling system isconsuming more energy than when the covering was in the initialposition, the motorized window treatment closes the covering to thefully-closed position.
 6. The load control system of claim 3, whereinthe motorized window treatment closes the covering from the initialposition to allow less sunlight to enter the space in response to thedemand response command when the heating and cooling system is coolingthe building.
 7. The load control system of claim 2, wherein thetemperature control device, in response to the demand response command,automatically increases the setpoint temperature of the heating andcooling system when the heating and cooling system is presently coolingthe building so as to decrease the power consumption of the heating andcooling system, and decreases the setpoint temperature of the heatingand cooling system when the heating and cooling system is presentlyheating the building so as to decrease the power consumption of theheating and cooling system.
 8. The load control system of claim 1,wherein the load control system monitors the heating and cooling systemfor a predetermined time period after the covering is moved from theinitial position to determine if the heating and cooling system isconsuming more energy than when the covering was in the initialposition.
 9. The load control system of claim 8, wherein the loadcontrol system stores data representative of energy usage information ofthe heating and cooling system in order to determine if the heating andcooling system is consuming more energy than when the covering was inthe initial position.
 10. The load control system of claim 9, whereinthe data representative of energy usage information of the heating andcooling system comprises values of a duty cycle defining when theheating and cooling system is active and inactive during thepredetermined time period, and the load control system monitors when theheating and cooling system is active or inactive to determine values ofthe duty cycles during the predetermined time period.
 11. The loadcontrol system of claim 9, wherein the data representative of energyusage information of the heating and cooling system comprises a rate atwhich the temperature decreases or increases in the space when theheating and cooling system is not actively heating or cooling the space,respectively, during the predetermined time period.
 12. The load controlsystem of claim 8, wherein the length of the predetermined time periodis approximately one hour.
 13. The load control system of claim 1,wherein the temperature control device transmits a request for energyusage information from the heating and cooling system in order todetermine if the heating and cooling system is consuming more energythan when the covering was in the initial position.
 14. The load controlsystem of claim 1, further comprising: a lighting control device forcontrolling the amount of power delivered to the lighting load, thelighting control device decreasing the amount of power delivered to thelighting load in response to the demand response command so as todecrease the power consumption of the lighting load.
 15. A method ofcontrolling a motorized window treatment comprising a window treatmentcovering for a window in a space of the building, the building having aheating and cooling system, the method comprising: moving the coveringto an initial position between a fully open position in which the windowis not covered and a fully-closed position in which the window iscovered; subsequently moving the covering from the initial position in afirst direction towards a fully open position to allow more sunlight toenter the space; monitoring the heating and cooling system for apredetermined time period after the fabric covering is moved from theinitial position in a first direction; storing data representative ofenergy usage information of the heating and cooling system in responseto monitoring the heating and cooling system; determining if the heatingand cooling system is consuming more energy than when the covering wasin the initial position by using the data representative of energy usageinformation of the heating and cooling system; and moving the coveringin a second direction opposite the first direction towards thefully-closed position if the heating and cooling system is consumingmore energy than when the covering was in the initial position.
 16. Themethod of claim 15, wherein the data representative of energy usageinformation of the heating and cooling system comprises values of a dutycycle defining when the heating and cooling system is active andinactive during the predetermined time period; and wherein monitoringthe heating and cooling system comprises monitoring when the heating andcooling system is active or inactive to determine values of the dutycycles during the predetermined time period.
 17. The method of claim 15,wherein the data representative of energy usage information of theheating and cooling system comprises a rate at which the temperaturedecreases or increases in the space when the heating and cooling systemis not actively heating or cooling the space, respectively, during thepredetermined time period.
 18. The method of claim 15, wherein thelength of the predetermined time period is approximately one hour. 19.The method of claim 15, further comprising: receiving a demand responsecommand; determining a calculated position of the sun; and determiningif the window is receiving direct sunlight in response to the calculatedposition of the sun; wherein the covering is moved in the firstdirection from the initial position in response to receiving the demandresponse command when there is direct sunlight on the window.
 20. Themethod of claim 19, wherein moving the covering in a first directioncomprises opening the covering from the initial position to allow moresunlight to enter the space in response to the demand response commandwhen the heating and cooling system is heating the building, and movingthe covering in a second direction comprises closing the covering if theheating and cooling system is consuming more energy than when thecovering was in the initial position.
 21. The method of claim 15,further comprising: wherein monitoring the heating and cooling systemcomprises receiving energy usage information from the heating andcooling system in order to determine if the heating and cooling systemis consuming more energy than when the covering was in the initialposition.